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- Gamut and Colour Profiles
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- Pantone and HKS
- PDF/X-4 and Other PDF/X Standards
- Process Standard Offset Printing
- Proof GmbH
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- Proof of EAN / GTIN Codes for Large Retailers like ALDI and HOFER.
- Proof Paper and Substrates
- Proof Profiles
- Proof Software and Technology
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Gamut map: The colour tool for cross-media design
Due to our involvement with freeColour e.V., at the last meeting in Switzerland the desire for a cross-media tool for designers was expressed with which one can create intersections of colourspaces from the freieFarbe CIELAB HLC Colour Atlas XL.
With Gamutmap, Proof GmbH has now created such a tool, which is available to all designers free of charge. With Gamutmap nearly 100 individual colour spaces can be indicated from 34.250 colours of the entire CIELAB colour space, or intersections from many combined colour spaces can be indicated.
An example: As a designer you are looking for colours for a new corporate design, which are available in sRGB for the internet, in ISOCoatedV2 for printing image brochures and in PSOUncoatedV3 for printing stationery. For video productions, the Rec.709 colour space is also to be taken into account.
In Gamutmap you can now easily select the colour spaces sRGB, ISOCoatedV2, PSOUncoatedV3 and Rec.709 and then click on “show”. After a few seconds you will only see the colours that are available in all selected colour spaces. If you move the mouse over a colour field, you will directly see the absolute colorimetric values of the colour in all selected colour spaces and you can copy them directly to your clipboard.
Since the hex value of the sRGB colour space was also still interesting, this colour space was additionally marked for display. The HLC and Lab values of all colours can be read directly in the colour table. All other colour values can be copied to the clipboard simply by moving the mouse to the desired colour field. For the colour field shown in the example above, it looks like this:
HLC: H005 | L055 | C035
Lab: 55 | 34,867 | 3,05
sRGB: 188 | 106 | 128
sRGB (HEX): #BC6A80
Rec. ITU-R BT.709-5: 188 | 87 | 115
ISO Coated V2 (ECI): 14 | 64 | 27 | 11
PSO Uncoated V3 (Fogra52): 10 | 70 | 34 | 8
Gamutmap is “Work in Progress”
We are sure that gamutmap will be a great help to many designers in creating cross-media corporate designs and are very happy that we were able to start and push the project with the members of freieFarbe e.V. For us, gamutmap is “work in progress”, which means: In the coming weeks we will add further functionalities and features to gamutmap. For example, a German version is in progress, and the download of spectral D50 CxF data of the selected colours should be possible in the future directly while hovering over the respective colour field, if the field is in the gamut of the freefarbe CIELAB HLC Colour Atlas XL. Further function extensions are already on our wish list… 🙂
We welcome suggestions, criticism, wishes and any support for the expansion and addition of Gamutmap.
Proof cheap. What does that mean?
Proof cheap is a typical search term that people use in search engines to find a cheap, colour and legally binding proof. But what makes a cheap proof?
A proof is one that is produced according to the specifications of the latest revision of the proofing standard ISO 12467-7 and is within the tolerances of this standard. The current revision is ISO 12647-7:2016, which has been tightened even further with this standard and has been supplemented by a certified edition of spot colours such as PANTONE and HKS.
Such certified proofs can be ordered at shop.proof.de for all proof profiles.
But what makes the certified proof cheap? That’s the low price. Proofs are printed on certified proof papers on very high-quality pigment inkjet printers, usually using expensive proofing software, and measured with spectrophotometers. So how can production be done cheaply here?
1: Using cheap pigment ink?
One litre of ink for proofing devices is around 400 EUR, so it makes sense to use inexpensive alternative ink from China. The problem: there are no manufacturers – neither in China nor anywhere else – who produce inks that would actually produce similar inks in terms of pigment colour and spectral composition. I once called a manufacturer who advertises that his – already quite expensive – inks could also be used for proofing. When I asked him, he said: “No, no, that’s just for advertising, but of course I would never do that or recommend it, and I don’t know anybody who does that. As for the China inks, he said: “They start at 20 EUR per liter, but you get a different ink with every delivery, depending on where the wholesaler buys. Then they have to re-measure the proofer every time… forget it.” In addition, replacing a clogged print head costs around 2,500 EUR, so the risk is too high. A real proof therefore only works with original, very expensive ink.
2: Using cheap software?
GMG ColorProof, EFI Fiery XF and ORIS Color Tuner are just some of the most important proofing solutions on the market. What they all have in common is that proofing software is rather a niche software, so the programming effort is very high compared to the sales figures. Depending on the size of the output device and the range of functions in terms of verification, spot colour display or proofing on special materials such as transparent foils, etc., the software costs between 5,000 and 10,000 EUR, and in combination with other software products from GMG or Colorlogic it can quickly cost considerably more. Although there are a few low-cost solutions here too, these are usually irrelevant in professional proofing, as they are either not suitable for more than one workstation, or important functions such as spot colour libraries etc. are missing.
Look back: Fogra Color Management Symposium 2020
The 7th Fogra Color Management Symposium was held in Munich from February 12 to 13, 2020, to which I was invited as a speaker for the area of proofing in Session 6. I reported on our tests in proofing for the Fogra58-Beta-Textile-RGB Standard for textile digital printing.
The Fogra Color Management Symposium is one of the events in the field of colour management and brings together scientists and users from all over the world for a two-day exchange of ideas in Munich. A total of 21 speakers and 7 moderators reported on the topics multicolour printing, proofing, print procurement, customer expectations, colour management for 3D printing and colour management for textile digital printing, the topic to which I was also assigned.
I arrived one day earlier, because there was a “Speakers Dinner” the evening before, and I also had to discuss with Jan-Peter Homann and Joe Tschudi the structure and selection of our patterns in terms of textile RGB. On site in Munich we set up the standard light booth LED Color Viewing Light XL HYBRID 2.0 provided by Just-Normlicht and coordinated once again which samples we would show best during the Color Management Symposium.
During the Speakers Dinner I had the opportunity to talk to Jürgen Seitz from GMG, the moderator of my session, and Jeffrey Stauffer from oneflexo GmbH, in order to organize our session on day 2 well. Gerardo Cerros from CMA Imaging Belgium SPRL, the third speaker of our session arrived directly for his presentation. Furthermore we could test our presentations on the Fogra computers and already got to know the lecture room and familiarize ourselves with the stage. On the stage sat the three speakers per session plus the moderator of the session. All presentations, moderations, questions etc. were translated live from English to German and German to English. I held my presentation in German, but I had kept the slides in “Denglish” so that they were understandable for Germans as well as for everyone else.
The complete programme of the symposium can be found on the Fogra website. The topics of the seven sessions were:
1. Managing customer expectations – Managing colours throughout the food chain
2. Creating colour credibility in CMYK and extended gamut printing
3. Real-world multicolour packaging implementations (ECG)
4. Industrial Printing application: High Speed Inkjet beyond commercial and packaging printing
KEYNOTE: Colour workflows in the motion picture world – How HDR & Wide Gamut change the game (Harald Brendl, ARRI)
5. Colour communication for fashion textile applications
6. Colour Proofing for Packacking & textile applications
7. Colour in 3D (3D Softproof & Appearance measurement)
You can download the presentation of my lecture “Proofing in textile printing: Contract proofs for RGB-(FOGRA58) based textile workflows” here
After the session, there were lively discussions at our Fogra58 stand and the fabric/proof comparisons exhibited were discussed. Special attention was paid to a pattern with different shades of grey by Joe Tschudi. The proof was quite neutral grey for the human eye, but the fabric had a clearly visible green cast. In terms of measurement, however, the two patterns were only DeltaE00 0.3 apart for an i1Pro2, and a ball-head meter also showed a similar distance. A nice example to demonstrate the difficulty between textile printing and proof, between measuring devices and human perception.
Fogra has issued a good conclusion of the proofing session here.
Many thanks to Andreas Kraushaar and the entire Fogra team for the excellent organisation and support during the entire Colour Management Symposium. An outstanding event that shows current developments in colour management and broadens the view to new markets and segments.
Update of shop.proof.de successfully completed
Shortly before Christmas, we initiated a major shop update, and adapted and improved numerous detail functions. But we are especially pleased that the update went without any major disruption for our customers, and that the shop was online and accessible for only a few hours, even though the update had to be carried out at the live shop.
The most important point for us was to update the upload area. The new file upload can now process up to 2GB per file and up to 50 files per article and: The upload now starts automatically, and does not need to be started first. We are thinking about increasing the file limit further here, but we really recommend our customers to simply zip many small files and upload the .zip file before uploading. This helps with the overview, and also helps us in handling.
Another new feature is that now all upload areas of all articles are uploaded in parallel and after successful upload all data is displayed appropriately for the articles. Only after the successful last upload the overview page is updated.
The overview of the loaded data has also improved.
Due to an updated shipping module we have more and more variable shipping methods at our disposal. Thus, starting next year, we will also be able to offer a UPS Express before noon, presumably parallel to the DHL Express before noon.
The most important point for us, however, is that the integration of the external modules has now changed so that we can import updates to the shop without having to touch all external modules at the same time. This will give us a lot of flexibility and allow us to respond even faster to better functions in the future and implement them in the shop.
A lot of changes in the background are security patches and an update to a current PHP version, which makes the shop overall more performant and secure.
Next year we are planning a graphical update of the shop before, which will make the website even clearer and faster.
EAN / GTIN test e.g. for ALDI 3B verification according to ISO/IEC 15416, ISO/IEC 15420
From now on we offer our customers the service to check EAN 8 and EAN 13 codes metrologically. This is important, for example, if you deliver articles for ALDI or HOFER, for which you have to provide proof of readability according to the so-called “3B” standard or better. You can order such an EAN GTIN barcode test report here in our shop.
For this purpose we check your EAN or GTIN code with a modern REA Check ER barcode checking device and prepare a test report according to ISO/IEC 15416 and ISO/IEC 15420:
- Symbol contrast
- Edge Contrast
- Modulation
- Rmin/Rmax
- Defects
- Decodability
- Rest area Left
- Rest area Right
- Bar deviation
- Code length
Other optional parameters are also checked:
- PCS (SC)
- Bright value (Rmax)
- Bar
- Gap
- Mean value
- Z-Module
- Size
- MF
- CPI
For example, in the “Size” field you can see directly whether your code corresponds to the size SC2 preferred by ALDI, for example. We have attached an exemplary evaluation above.
For the measurements we need original packaging with your printed EAN / GTIN codes. All codes will be checked on the day of their arrival and the test reports will be sent to you the same day.
Epson launches new generation of proof printers SureColor SC-P9500
In late 2019, Epson will present its new generation of proof printers: the Epson SureColor SC-P9500 and SC-P7500 proof printers.
Epson has incorporated many improvements into the new printer generation. For example, fully loaded print heads now work in the new printers, which can finally handle photo black, matt black and the two grey tones LightGray and LightLightGray as well as the colours orange, green and violet simultaneously in one print head. For cyan and magenta there are also the light variants light-cyan and light-magenta, so that besides yellow, cyan and magenta, 12 full colours are available in the print head. The printer uses the new UltraChrome Pro12 ink set, which could possibly bring some detail improvements to the classic K3 inks, although nothing more is known about this yet.
Proof GmbH is now four times Fogra and Fogra “Spot cert” certified
This year we have again submitted proofs for Fogra certification. We thus prove that we not only deliver outstanding proof quality through internal quality controls and checks, but that the quality of our proofs is also confirmed by an external body. We have therefore had proofs certified for the seventh year in succession.
In 2019 we have made two innovations in Fogra certification.
- We were certified for the first time for the new standard Fogra 54
- We have also carried out a certification for PANTONE spot colours for all four printing conditions, the “Spot cert”. We have certified the spot colours PANTONE 2270 C, PANTONE 151 C and PANTONE Cool Gray 6 C for the proof standards ISOCoatedV2, PSOCoatedV3 and PSOsc-b_paper_v3 and PANTONE 2270 U, PANTONE 151 U as well as PANTONE Cool Gray 6 U for the standard PSOUncoatedV3
The quality of our prints and our spot colour reproduction of the PANTONE colours was confirmed by Fogra for all four proof standards.
The complete 14-page Fogra test report can be downloaded here.
These new certifications have been implemented on the current software revision Fiery XF 7.1.3 and have been applied to the papers EFI Gravure Proof Paper 4245 Semimatt, EFI Proof Paper 8245OBA Semimatt and EFI Proof Paper 8175OBA Matt.
Good times: The general meeting 2019 of freieFarbe e.V. in Switzerland
After the association freieFarbe e.V. had met last year in Tübingen for their annual general meeting, this year we met in a rustic hut in the Appenzeller Land, which Peter Jäger from pre2media and Eric A. Soder from pixsource.com had excellently chosen, just like the sunny weather that should accompany us from Friday to Sunday.
The chairman of the association, Holger Everding from DTP Studio Oldenburg and Jan-Peter Homann from Homann Colormanagement in Berlin arrived in Tübingen on Thursday, and after a first long night full of discussions and a meeting in the Proof.de office on Friday morning around noon, the three of us continued our journey to Switzerland. After a joint dinner with Peter Jäger and Eric A. Soder (from Tübingen, we had taken some Swabian potato salad and my handmade Maultaschen with us the evening before), an evening full of planning and a strategy workshop for the tasks and goals of the next year began. Without question, this evening was also spent discussing, developing, laughing and working creatively until late into the night between Flensburger Pils, Swiss mountain beer and wine in attractive red and light yellow shades.
After breakfast, we continued on Saturday to swissQprint, where we had the opportunity to learn more about the status quo of large format digital printing from association member Guy Flüeli, as well as visit the production facilities and conduct print tests on the Karibu and other SwissQPrint presses.
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Holger Everding, Guy Flüeli, Jan-Peter Homann -
Showroom swissQprint -
Michael Jakobi, Matteo Baschera, Martin Spaar, Matthias Betz, Guy Flüeli, Jan-Peter Homann
Convert PANTONE colours optimally into CMYK. Practical aspects to the new old discussion.
A very frequent topic for us in the area of proofing is the optimal conversion of PANTONE colours in CMYK for classic, inexpensive four-colour printing. In the last few days, there has been a lively discussion on this topic in the Adobe Forum and in the colour management forum of hilfdirselbst.ch, which I would like to summarise briefly, as our customers often struggle with the same issues.
PANTONE and the PANTONE CMYK values from Bridge: The Problem
The central question is to which standard or colour profile a CMYK value of a PANTONE colour in Bridge actually refers. Specifically, a user asked for the conversion of PANTONE 116 C, a colour tone that is specified in the PANTONE Bridge fan in CMYK 0/14/100/0 (here you can see the original value in PANTONE). But if you now convert the underlying PANTONE Lab color value in InDesign or Photoshop into different CMYK profiles, you will get different, significantly different color values. “What does the PANTONE Bridge CMYK colour value refer to” was the original question of the discussion.
The starting point of the PANTONE Bridge fan
In the PANTONE Bridge Fan, “equivalents” of the PANTONE spot colours on a coated and an uncoated paper grade, separated with 4 Pantone scale colours, are visualised and the CMYK values are specified.
But one thing is clear: without precise information on the substrate, print density, inks used, etc., the information provided there has only limited validity. If, for example, one converts the LAB colour value of PANTONE 116 C into the SWOP Web coated commonly used in the USA, then one reaches a value of 20 in magenta instead of 14 as indicated in the PANTONE Bridge Fan.
Comparison of PANTONE LAB values with PANTONE Bridge CMYK values in PSOUncoatedV3 and PSOCoatedV3
If you compare the original PANTONE LAB values and the PANTONE Bridge CMYK values in European standards such as ISOCoatedV2 or PSOCoatedV3 for coated or PSOUncoated or PSOUncoatedV3 for uncoated paper, there are sometimes serious colour deviations. The PANTONE Cool Gray 2 is much too light in CMYK conversion, the PANTONE Cool Gray 11 is always much too dark. For the PANTONE 3278 C, the Bridge CMYK value for PSOCoatedV3 fits quite well, but the same comparison for Uncoated is noticeably worse. What is the reason for this?
The question was therefore specified once again:
- How can PANTONE specify “official” CMYK values for a particular colour if it is not clear what paper white, print density, ink coverage, etc. the values refer to?
- How does PANTONE arrive at the specified colour values?
- Which ICC profiles are possibly the basis?
- Are there errors if programs such as Photoshop or Affinity Publisher do not show the same values when converting a Pantone color as those specified by Pantone?
Thesis 1: Why should a spot colour manufacturer deliver perfect CMYK replacement values for his products? That would be detrimental to business.
One thing is clear: there are no system errors. PANTONE knows what they do. But it is surprising that the bridge values have apparently been fluctuating by several percentage points for many years. Perhaps one reason for this is that different base pigments have been used over the years and the values have therefore been adjusted. But it was not possible in any way to find out how the values are created, what profiles or logic could be behind the values. Some discussion participants thought of a deliberate system error: “Cui bono? Why should a spot colour manufacturer deliver perfect CMYK replacement values for his products? That would be detrimental to business.”
This is an exciting approach which, at second glance at the latest, does not lack a certain logic. If the head of the company has only seen bad CMYK conversions of his PANTONE spot colour for long enough, he will sigh and agree to any surcharge for a five-colour print, only to finally find his corporate colour correctly reproduced again.
But another thesis is also very plausible:
Thesis 2: The sales department defines the CMYK values
Let’s assume that a PANTONE “Green1” corresponds colorimetrically to a CMYK of 30/0/100/0. If two more saturated green tones (“Green2” and “Green3”) are displayed in the fan, which theoretically should be displayed with CMYK 35/0/110/0 and CMYK 40/0/120/0, what then?
To set all three green tones to CMYK 30/0/100/0, i.e. the next CMYK value that can be achieved absolutely colorimetrically? That would actually be the most obvious way, especially since it is very unlikely in practice that two adjacent PANTONE colours would ever be used in CMYK conversions. Because a company has either green1 or green2 as its corporate colour, but hardly both at the same time.
On the other hand, buyers of PANTONE Bridge fans would probably be very surprised if different PANTONE colours in the fan had the same CMYK value.
Therefore, a psychological-sales-department correction is obvious: In order to avoid identical CMYK values, we set the most saturated green tone to the not matching CMYK 30/0/100/0, and then the less saturated colors to 25/0/0/90/0 and 20/0/0/80/0, i.e. also not matching CMYK values. Now nothing fits anymore, but at least all colors have different CMYK values.
Practice shows: An adjusted conversion via ICC profiles often provides a better CMYK color value for the conversion of PANTONE colors like the CMYK value from the PANTONE Bridge.
We have converted the PANTONE colours used in the above mentioned graphics also via ICC profiles partly absolutely colorimetrically and relatively colorimetrically with depth compensation (marked with an “r” behind the CMYK colour value) into the two output colour spaces PSOCoatedV3 and PSOUncoatedV3 and have mapped the visually best match in each case.
In most cases, this conversion adapted to the output color space delivers the significantly better results. See for yourself:
We support you in determining the optimal CMYK conversions for your PANTONE house colours
If you need the best possible conversion of one or more PANTONE colours to CMYK, we will be happy to support you with our know-how and our measuring and proofing technology. We determine and compare different imaging variants of a PANTONE colour in CMYK and show you the best determined conversions in CMYK with metrological evaluations in Delta-E00.
Paper white from Arctic Paper, Surbalin from Peyer and more added
We have added 140 additional paper white values from Arctic Paper, Peyer, Igepa, Antalis and Mondi. As a result, a total of almost 1400 paper whites are now available in our database.
From the company Peyer we have added the colour shades of the Surbalin product range, although we have not covered all surfaces individually here. However, we have now also included other Peyer products such as Peytan, Peydur, Peyprint and Comet in the paper white database.
You can find the paper white database at shop.proof.de:
https://shop.proof.de/en/info/paper-white.html
How to match the production paper, proof standard and the proof precision of spot colours
Today a customer called who wanted to order a proof of several HKS N spot colours on an uncoated paper. “Which proof profile should I choose? And how exactly can you match my special colours in the proof? I probably have to proof several HKS N red tones in comparison. By the way, the printing is to be done on Fly Cream, a slightly yellowish paper.”
What is the paper white of the production paper?
First of all, I searched with the customer for the production paper in our paper white database. A quick look via full text search revealed that we have measured Fly Cream from Papier Union:
With a B-value in LAB of 9.2, Fly Cream is really not just a little yellowish, as the customer said, but clearly yellowish, chamois, creamy … whatever you want to call it. So it was natural to check the proof profile “ISOUncoatedYellowish”, Fogra 30, to see to what extent the paper white could match.
What is the paper white of the possible proof standard?
Together with the customer we looked up our “paper white of proof profiles” table:
Contrary to the customer’s expectations, the paper white of ISOUncoatedYellowish is not even as yellowish as the paper white of the edition paper Fly cream, which is more yellowish by more than 5 steps on the B axis. So it was clear: PSOUncoated as a brighter-free uncoated paper proof standard is clearly too white, ISOUncoatedYellowish is much more suitable.
On what kind of proof paper will this proof standard be printed?
Which proof profile for corrugated plastic posters and election posters?
As is well known, elections are always around the corner, and the trend towards ever larger and more numerous election posters is unbroken. In the past, only Mother Nature made the landscapes colourful in spring, but today every local, state, federal and European election does so easily. Every candidate, every large or small party now has the technical and financial means to transform entire streets into a colourful sea of messages and faces. Once the photographer has captured the election candidates well in the studio, the pictures go off for retouching and then for layout.
Until a few years ago, election posters were usually produced in classic offset printing and then glued onto hardboard with paste, drilled or screwed onto roof batten stands and then attached to street lamps with wire. And if the election took place in the summer, the posters were printed in a double edition, so that in an emergency the faded prints could be pasted over and refreshed with new ones after one month for the final spurt.
Today, however, the corrugated plastic poster is becoming more and more popular, as it is supplied pre-drilled and ready to use, retains its colour for several months and can be attached to street lamps with cable ties. But how should print data be created and how should data be prepared and proofed?
All manufacturers of corrugated plastic posters and election posters known to us want proofs in ISOCoatedV2 or ISOCoatedV2 300%
Corrugated plastic posters are produced on different systems. Sometimes four colours are used, sometimes six, sometimes more colours. Therefore, there are no binding proof standards for most digital print products produced in this way.
Instead, it works the other way around: Since most of these digital printing systems have at least the colour gamut of offset printing on picture printing paper, these printing systems are based on the established colour gamut of ISOCoatedV2.
For example, Printpartner-XXL writes: “For colour-critical motifs, we therefore recommend a prepress proof on the original material or the delivery of a colour-binding proof (with media wedge and date). Data that is delivered without colour information is provided and produced with the standard profile “ISO Coated v2”. In such a case, a colour complaint cannot be accepted.
Eine Reklamation der Farbe kann in so einem Fall nicht anerkannt werden.
From our point of view, most printing specialists demand ISOCoatedV2, some like flyeralarm and wir-machen-druck ISOCoatedV2 300%. Some want black exclusively as pure black, some exclusively as CMYK 50/50/50/100 colour black … and some do not give any information about the required colour profiles … but if you don’t specify anything, you probably won’t stick to anything … so if you want to be on the safe side, you should choose a supplier with a functioning colour management system and specifications for colour profiles.
eciCMYK profile available for proofing
Today we have activated the exchange colour space eciCMYK, Fogra53 for proofing and integrated it into the online shop of proofing.de for ordering.
eciCMYK is the colour space for CMYK print production and complements the other Fogra colour spaces, but in contrast to these it does not represent a specific printing process, but is rather “neutral CMYK”. Due to the large gamut of eciCMYK all classical printing processes can be represented, it can be proofed on modern proofing systems without any problems and corresponds in its characteristics to typical CMYK printing colour spaces.
Proofs in eciCMYK / Fogra 53 can now be easily ordered in our Proof Shop, you can select the profile directly when ordering.
Further information on Fogra 53 can also be found on the homepage of the European Color Initiative ECI. Andreas Kraushaar from Fogra also presented the colour space in the Fogra aktuell issue 201, which you can download for free.
PANTONE and HKS colour deviations in proofing updated
Current proofing systems can reproduce spot colours such as HKS or Pantone very well. With the Fiery XF 6.5.2 proofing software and the Epson SureColor-P9000V Spectro proof printer, we have evaluated the colour deviation in Delta-E00 with which the various PANTONE and HKS colours can be proofed. On shop.proof.de, the tables are now available for all important PANTONE and HKS colour systems, sorted by colour fans.
A distinction is made between the proofing substrates that we use, since the surface texture and the paper white also have an influence on the representability of the colours. The colour deviations were calculated by the proofing software on the basis of the measured colour space of the proof.de proofing system. Deviations are therefore possible in practice. However, it turns out that almost all spot colours can be simulated quite well in the large colour space of our proofing devices. The smaller the ∆E00 value, the smaller the colour distance from the spot colour reference to the proofed colour. Higher ∆E00 values show which colours can be reproduced more poorly in the digital proof.
As a rough guide: From ∆E00 > 1 a colour difference is visible to the human eye, below it it can only be measured, but not seen.
Paper white of many paper manufacturers and online printers measured
We spectrally measured the paper white tone and the proportion of optical brighteners of over 1,000 papers of the most important paper manufacturers such as Berberich and Papier Union as well as online printing companies such as Flyeralarm and wir-machen-druck.de.
Only a few paper manufacturers currently publish data on paper whiteness and the proportion of optical brighteners in their papers, but only technical indicators such as whiteness according to ISO 2470-2 or CIE ISO 11475. However, designers can hardly record paper whiteness with these values. In addition, it is not possible to read from these data whether and what proportion of optical brighteners the paper has.
Example above: Spectral data comparison of Antalis Coqueror CX 22 white for the measurement standards M0 and M1. Below you can also see the color deviation in Delta-E00 of 1.97 and the two paper white values in LAB and LCH.
Left: CGATS.17 Data for measurement conditions M1 and M0 for paper Antalis Conqueror CX 22 white
We have therefore measured the most important papers and dyes of all central paper producers and paper distributors as well as online printers in the three measurement standards M0, M1 and M2. From the difference in the paper whiteness of the two measurements M2 (UV cut without UV portion) and M1 (ISO 3664:2009 with noticeable UV portion), we determined the color distance on the yellow-blue axis of LAB in Delta-b and derived from this the proportion of optical brighteners according to Delta-B according to ISO 15397 and evaluated it.
Delta-B conversion: OBA share in the paper
Delta-B < 1 = faint OBA
Delta-B < 4 = little OBA
Delta-B < 8 = low OBA
Delta-B < 14 = moderate OBA
Delta-B > 14 = high OBA
Spectral data of all measured papers for download
Parallel to the images of the spectra, we have also provided spectral data in CGATS format for the measurement modes M0, M1 and M2, which can be downloaded for any paper. These values can be used, for example, in proofing software to calculate a paper white simulation for a specific production paper.
free colour: CIELAB HLC Colour Atlas XL published and can be ordered at proof.de
After almost a year of work the time has finally come. The CIELAB HLC Colour Atlas XL saw the light of day. The new HLC Colour Atlas XL is the basis for all stages of professional colour communication – from design to the finished product. The standard version contains 2040, the new XL version even 13283 mathematically-systematically graded CIELAB colour tones on 74 pages.
You can order the CIELAB HLC colour atlas here in our shop
The free file package contains the layer PDF version with several gamuts for the analysis and research of colors, as well as the spectral data (380-730 nm) of all color tones for recipe software, an Excel table with the measured values and spectra as well as color value tables for all common CMYK color spaces and sRGB. All files are available for free download under a CC license.
Only the HLC Color Atlas XL printed by Proof GmbH is subject to a fee, as production is very labour-intensive and cost-intensive. We at freieFarbe e.V. and Proof GmbH see the “CIELAB HLC Colour Atlas XL” as a genuine, transparent and high-precision alternative to the hundreds of proprietary colour systems, which often make fast and precise cross-media communication in design and production very difficult.
Proofs for recycled paper. Is that possible?
We produce proofs for classic white uncoated papers on a daily basis, but the question often arises as to which proof standard could be used for printing on recycled paper.
In general, the paper white in a proof is precisely defined in the proof standard and is also measured in every test report.
For PSOUncoated it is 95.00 / 0.00 / -2.00 in CIELAB and for PSOUncoatedV3 it is 93.50 / 2.50 / -10.00, i.e. slightly darker (93.50 instead of 95.00 for brightness L) and significantly bluer (-10.00 instead of -2.00 on the B axis, i.e. the blue-yellow axis in the blue direction).
Recycling papers differ not only greatly from type to type in the area of paper white, but even from batch to batch. So if a printing company orders the same recycling paper in January and in February, the paper mill may well deliver a slightly different white value of the paper, as the paper white of course depends strongly on the recycled paper qualities used for production.
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Recycling papers
White-point sample 1 -
Recycling papers
White-point sample 2 -
Recycling papers
White-point sample 2
A colour-binding proof for recycling paper is therefore not possible, as no standard has ever been worked out due to the different paper qualities and white tones.
It is recommended for the proof to choose a classic proof standard such as PSOUncoated / Fogra 47, which shows a rather neutral, unbrightened paper white in the proof. Place one side of the recycled paper next to the proof and mentally transfer the colour of the proof to the white tone of your recycled paper. This way you can imagine the later printing result quite well.
DIN SPEC 16699 “Open colour communication” published
A few days ago, our DIN SPEC 16699 “Open Colour Communication” was published and is now available for free download from DIN’s Beuth-Verlag.
Matthias Betz from Proof GmbH, Holger Everding from DTP Studio Oldenburg, Jan-Peter Homann from Homann Colormanagement in Berlin and Eric. A Soder from Pixsource in Switzerland, all members of the association freieFarbe e.V., have shown in the bilingual DIN specification a way to create high-precision color samples on the basis of open source, license-free standards and have shown ways for cross-media color communication.
The 44-page PDF is bilingual in German and English and can be ordered directly from Beuth Verlag, which distributes the DIN standards in Germany, and downloaded free of charge after a short registration.
Why is the embedding of RGB profiles so important?
A few days ago we received a call from a customer in the field of design, who sent open Adobe InDesign data in ISOCoatedV2 300% with contained RGB images to the production company for a complex CD production on the advice of the producing company (“The printing company still has a prepress stage, which can then prepare your data optimally…”). The result of the finished printed CD booklets and inlays did not correspond at all to the calibrated monitor image of our customer, the client was also unhappy and requested the print data about the production company from the print shop responsible for the print to troubleshoot. Data in the “US Web Coated” color space with 350% ink coverage came back from the printer. For troubleshooting, the customer then had a proof of his data created by us, but had chosen the settings “Convert to target profile (retain values)” as usual when writing the proof PDF; we thus received completely CMYK data, of which we produced a proof according to ISOCoatedV2 300%, which completely met our customer’s expectations. So it seems that the designer created the data correctly and printed the print shop incorrectly.
On closer inspection, our error analysis revealed two serious weaknesses:
- On the one hand, the obviously wrong profile conversion of the print shop with InDesign CS2 to “US Web Coated”, a completely outdated profile never used in Europe, which was delivered with early Creative Suite versions and was probably never adapted due to a lack of competence on the part of the print shop.
- On the other hand, the open InDesign file of our customer, which he had sent to the production company, contained RGB images without a profile (DeviceRGB), which cannot be safely interpreted.
In this case, a complaint of the designer to the printing company will of course be difficult, as on the one hand, non-profiled RGB data were sent to the production company, and on the other hand, no print PDF generated by the data creator in the correct output color space ISOCoatedV2 300% was supplied.
If this had been done, one could at least have argued that the expected color of the production print would have been comprehensively known. Thus, one can only refer to the fact that the printer would have had to ask the designer for RGB data without an embedded color profile, and should not have assigned the data somehow to a profile “blindly”. The fact that the print shop with its crude US Web Coated workflow certainly did not create a correct print file, but a wrong one for the output, can indeed be stated, but the print shop can always talk its way out to “systems with in-house standard”.
How do we deal with RGB data at Proof.de?
If we receive a PDF file that contains RGB images, the next step is to check if the file is a valid PDF/X-3 or PDF/X-4. If this is the case, we check whether all input RGB profiles are correctly marked with color space (sRGB / AdobeRGB / ECI-RGB-V2 etc.) and rendering intent, then we check whether the correct output color space was used as output intent and whether also contained CMYK data have the correct input profiles. If yes, then we proof the file with the settings: “Consider all input and output color spaces”.
In this case, the file is reproduced 100% exactly as our customer created and defined the color profiles. If he has made a mistake and e.g. marked an image with a wrong RGB profile, this will also be “incorrectly proofed” exactly as correctly.
If RGB data should not contain a profile, e.g. if they are created in Device RGB, we generate a “data incorrect” e-mail in which we explain our procedure as follows:
“Dear customer, the data check has shown that RGB elements are contained in your data. RGB elements can only be safely interpreted in the proof if they are marked with a color profile and a rendering intent. This is the case, for example, with correct PDF/X-3 and PDF/X-4 data. The correct output intent must also be specified.
At least one of these criteria does not seem to be the case for your file. The safest way would be to convert the contained RGB data to CMYK. This has the advantage that you have control over the conversion and can view the CMYK result again in Acrobat before uploading the file again for proofing. We can then reliably use your CMYK values for the proof. To do this, call up the current order in your customer account, delete the incorrect data and upload the corrected data.
If, for example, the RGB element should only be a small image that is not relevant for the overall impression of the proof, or if you do not have another file available for the proof, then of course we can also use your RGB data for the proof. If available, we use your RGB source profiles and rendering intents, otherwise we use the sRGB standard and the rendering intent “relatively colorimetric with depth compensation”, which in most cases will lead to correct proof results. If you would like us to proof the supplied RGB data in this way, please let us know. Please do not hesitate to contact us if you have any questions. Best regards, your proofing team”.
In our case, the CD production case would also not have occurred in the proof, as we reject RGB data not provided with an ICC profile with the error message mentioned above, and do not convert them, as we cannot predict precisely how our customer would have liked the data to be converted.
We are aware that our approach is not 100% the ultimate best approach in all cases, but to the best of our knowledge and belief it is best in line with market practice and the expectations of our customers.
However, we are also happy to accept your individual requirements and circumstances. Give us a call or send us an email and describe your processing requirements.
Colour Management Consulting and Expertise
By the way: We are happy to put our knowledge and data competence at your service: If you also have a problem, a question about print data, data preparation, or – as in the above example – a misprint has already occurred and you need external expertise and assistance for the complaint: Give us a call. We will be happy to advise you and help you where we can help. We will charge you for our advice and analysis at an hourly rate of EUR 90,- plus VAT, and you will be billed for 15 minutes each. An initial consultation and assessment is of course free of charge.
How CMYK and RGB profiles are handled in proofing
When we receive a file from you, the first thing we check is whether there are colours other than CMYK in the file. If the file is built exclusively in CMYK, it will be sent directly for proofing.
Handling wrong profiles with CMYK data / “Profile Mismatch
If we have only received CMYK data from you, we will ignore all input and output profiles and only use the CMYK values that we bring to the ordered output colour space.
Example 1: Data in ISOCoated, proof in ISOCoatedV2 ordered, thus wrong or no CMYK profile embedded.
You send a file with the profile ISOCoated and a colour area in CMYK 100/70/0/0 and order a proof according to ISOCoatedV2.
We ignore the ISOCoated profile and proof the pure colour value 100/70/0/0 according to ISOCoatedV2.
Why do we do this?
In our proofs, we try to reproduce the “lived reality” of the print as well as possible. In many conversations with printers we have seen that in almost 100% of the cases they do not convert profiles from CMYK to CMYK, but instead put a colour value of 100/70/0/0 on the plate without taking CMYK profiles into account, insert paper and print in conformity with the standards. So we also map this way, although it would actually be “more correct” to perform a colour space transfer from ISOCoated 100/70/0/0 to ISOCoatedV2. However, this results in a different colour value, for example 100/63/1/6 for relatively colorimetric conversion with depth compensation or 100/63/3/15 perceptively with depth compensation!
In practice:
One of our customers did not proof 30 slightly different, dark blue colour areas in ISOCoatedV2 on our premises, but on the premises of a colleague, under each of which the CMYK value was in black lettering, in order to sample the colour of a powder-coated surface. The customer defined a very well fitting CMYK colour value on the basis of the proofed colour areas, inserted it into his brochures and started the print jobs. Result: The dark blue was a distinctly different blue than on the reference proof, customer and agency were very dissatisfied and went on troubleshooting. Now the case came to us.
We received a file for proofing according to ISOCoatedV2 and compared it with our colleague’s proof. The colours with the same black CMYK values printed underneath were clearly different, but both proofs were provided with media wedges and measured correctly. After some troubleshooting, we came up with the idea of requesting the original proof from our colleague, which also existed. In this one there was a Fogra27Coated profile, thus an implementation of the old ISOCoated. A proof according to ISOCoatedV2 had been ordered at that time. Had it happened? The colleague had taken the input profiles into account, which resulted in a significant change in the CMYK values of the colour patches, as mentioned above, due to a colour space transfer from CMYK to CMYK. The black printed CMYK values under the colour patches had of course not changed. The patterned CMYK value therefore did not correspond to the proofed value at all. Our customer fell from all clouds: “How, our CMYK values were not proofed”. This would not have happened with us, because we would ignore the embedded profile with CMYK data. In this case this would also have been our customer’s expectations.
After almost two hours, we had determined the “error” (or perhaps rather: the “difference”), created a proof for our customer that was “in line with expectations”, which he could use to determine the appropriate CMYK value in ISOCoatedV2, and solved the problem. (more…)
You can easily order proofs from our shop:
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Proof GmbH
Gölzstraße 17
72072 Tübingen
Baden-Württemberg
Germany
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