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.

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.

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

Colourmanagement Consulting
Colourmanagement Consulting

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…)

Adobe Color Picker 2019: Decimal places possible in InDesign and Illustrator

Adobe has updated its colour picker in the 2019 version. Especially in Adobe InDesign 2019, decimal places are now possible for LAB and CMYK during colour input, which is a long-desired feature especially in the high-end colour area. Up to now it was already possible in Adobe InDesign to enter colour values e.g. in CMYK with decimal places and to write them into the PDF during PDF export, but only integer values were displayed.

In Adobe InDesign 2019, three decimal places can now be entered for LAB and CMYK and can also be read out again. However, these values are not adopted in the automatic labelling of the colour fields, although this can always be adjusted manually.

In Adobe InDesign 2019 können jetzt bei CMYK und LAB Werte mit bis zu 3 Nachkommastellen eingegeben werden.
In Adobe InDesign 2019, values with up to 3 decimal places can now be entered for CMYK and LAB.

Also in Adobe Illustrator 2019 CMYK inputs with decimal places are now possible, although only two decimal places are possible here. With LAB, only an integer entry is still possible.

Adobe Illustrator 2019 Farbwähler CMYK Eingabe mit zwei Nachkommastellen
Adobe Illustrator 2019 Color Picker CMYK Input with two decimal places
Adobe Illustrator 2019 Farbwähler LAB Eingabe nur ohne Nachkommastellen möglich
Adobe Illustrator 2019 Color Picker LAB Input only possible without decimal places

Only Adobe Photoshop still does not allow any decimal places, but only whole numbers, it does not matter whether the file is in 8Bit or 16Bit. This applies equally to LAB, RGB, CMYK and grayscale: In none of the colour systems is a specification with decimal places allowed.

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The 10 best colour websites to inspire designers

Designers constantly need to be inspired to create new colour creations. Often pictures are chosen as the starting point for a new colour composition. Or there is a leading colour for which further colours must be found in order to create a harmonious colour palette.

There are several websites on the net that are perfect for such colour breakdowns and colour inspirations for graphic artists and designers. We have summarized the best of them here in an overview.

1. Adobe Color CC, formerly Adobe Kuler:

Adobe Color CC is the Adobe social colour network. Designers can test and evaluate colours and develop different colour schemes and colour combinations. These can then be downloaded directly for use in Adobe products such as Adobe Creative Suite. https://color.adobe.com

adobe_color_cc

2. COLOURlovers.com

On Colourlovers, users can create colour palettes, rate them and exchange information in blogs. In addition, the site offers numerous articles on colour, shapes and much more. http://www.colourlovers.com

colourlovers

3. colorcombos.com

With Colorcombos, users can experiment with different colours and colour (more…)

Is it possible to proof on special paper such as production paper?

“We print 135gr/sqm on a Berberich Allegro. Can you make us a proof on this paper? Can you proof on our final production paper?”

Our telephone support often asks for a proof on production paper. Unfortunately, we always have to answer the question negatively. I would like to briefly explain the reasons for this in the following article.

Proofing on production paper is still technically impossible.

All proofing systems currently certified by Fogra are based on an inkjet printer as a test printer, mostly from Epson, Canon or HP. These printers are characterised by a large colour space, good resolution and excellent homogeneity and colour stability – all characteristics that are absolutely necessary for a proof printing system. The Epson systems used by the majority of proof printers are based on 11-colour pigment inks, which can reproduce a significantly larger colour space than e.g. ISOCoatedV2. However, the prerequisite for this is the use of special papers optimized for inkjet printing, in which the pigments and inks are optimally emphasized. This requires special coatings that are optimized for optimum reproduction, fast drying, good abrasion resistance and high UV stability of the print. On an image printing paper without these coatings, the ink would run, hardly dry and would not be smudge-proof. The color space would also be impossible to achieve. A proof would therefore not be possible from this point of view. (more…)

Reproduction of anaglyph images and line drawings

Already a few weeks ago we received an unusual request: The musician and aspiring art student Tobias Weh from Osnabrück experimented with line drawings based on anaglyphs and achieved very good results on the monitor. He created superimposed line drawings, which then delivered a different image when viewed through the left eye than when viewed through the right eye. The question was whether this could be reproduced better with the high color range of a proofing system than with a simple domestic inkjet printer.

Since such questions are of course very interesting at first sight, we were quickly prepared to support Mr Weh in his work. To get closer to the matter, we use an i1 Pro 2 and BabelColor Color Translator & Analyzer to measure the spectra for the two films, which are transmitted through standard anaglyph glasses.

Anaglyphenbrille - Durchgelassenes Spektrum der beiden FolienActually a very satisfactory result. By choosing two colours as printing in the spectral ranges of 450 to 500 nanometres for blue and 650 to 700 nanometres for red, it should actually be possible to achieve quite a good result. (more…)

Ten points that you should always keep in mind when proofing.

It is actually quite simple to have proofs made. But experience shows that many customers often stumble over the same mistakes. We have put together the ten most important steps towards a successful proofing job:

  1. Proof as late as possible in the production process
  2. Select the right proof profile for your purposes
  3. Convert RGB or LAB images to CMYK
  4. Name Pantone and HKS colours correctly
  5. Proof your data in a 1:1 ratio and not scaled down
  6. Always proof with UGRA/Fogra Media Wedge 3.0
  7. Make sure that the job ticket is correct
  8. Make sure your service provider has the latest proof software and hardware
  9. Only accept authentic “contract proofs” according to ISO 12647-7
  10. Make sure that your proof provider has valid certifications

In the following we would like to present these individual points in more detail.

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Pantone Plus vs. Pantone: Colours, fans and problems.

In 2010, one of the central innovations at Pantone was the new system for graphic designers, service providers and printers: The Pantone palette was extended by numerous colours and was given a new name: Pantone Plus

The extension by 560 colours was done in two steps:

 2010: 224 added to a total of 1341 Pantone Solid colours

In 2010, the Pantone palette was extended by 224 colours, which are named from 7548 to 7771 in the Pantone classification. All new colours could continue to be mixed with the previous 14 Pantone basic colours in the print shop.

  • PANTONE Yellow
  • PANTONE Yellow 012
  • PANTONE Orange 021
  • PANTONE Warm Red
  • PANTONE Red 032
  • PANTONE Rubine Red
  • PANTONE Rhodamine Red
  • PANTONE Purple
  • PANTONE Violet
  • PANTONE Blue 072
  • PANTONE Reflex Blue
  • PANTONE Process Blue
  • PANTONE Green
  • PANTONE Black

 2012: Another 336 more to a total of 1677 Pantone Solid colours

In 2012, the Pantone Plus palette was expanded by additional 336 colours, which in the Pantone classification are named from 2001 to 2336. In order to achieve these colours, the previous 14 Pantone base colours were extended by 4 new colours to a total of 18 base colours. The new colours borrowed from the Pantone GOE palette are:

  • PANTONE Bright Red
  • PANTONE Pink
  • PANTONE Medium Purple
  • PANTONE Dark Blue

Unfortunately, Pantone did not communicate these changes very well. A typical example can be seen in a screenshot from November 8, 2013: On the German and English Pantone pages, there are two completely different numbers for new colours; only the total number of colours on the two Pantone country pages is the same.
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What is Moiré? And can I see Moiré in a proof?

The Moiré effect, or in other words a halftone screen overlay, is a common phenomenon when viewing prints. It occurs when two even patterns overlap unevenly.
Moiré Effekt

When does Moiré appear?

Moire is always created when screens overlap. Typical examples:

  • You have scanned in a newspaper ad and print it in another newspaper.
  • You print the portrait of a managing director wearing a jacket with a fine houndstooth pattern, a checkered shirt and a finely patterned tie. Regardless of the printing process, complete moiré chaos is guaranteed to break out here.
  • A brick building is reproduced in offset printing.
  • The photograph of a ventilation grille is viewed on a monitor (more…)

Easy conversion of Pantone – HKS – CMYK – RGB with Adobe Photoshop

Farbbücher Auswahl in Adobe Photoshop CC: HKS, Pantone, CMYK und vieles mehr

More often the question arises as to what kind of Pantone colour corresponds to the HKS 43 K. Or what CMYK value? And what kind of web color in RGB?

If you own Adobe Photoshop, you can do these conversions directly there. In Photoshop CC all well-known color books are stored with values.

Let’s assume we are looking for the Pantone equivalent and the matching CMYK color of HKS 43 K.

1: Open the color palette in Adobe Photoshop and select HKS K as the book and then the color HKS 43 K. All well-known colour books are directly stored in Photoshop.

Farbauswahl von HKS 43 K im Buch HKS K in Adobe Photoshop CCThe color corresponds to a Lab value of 26/29/-79 and a CMYK value is already stored here. Simply select the book HKS K Process: (more…)

Layout in RGB, print in CMYK. Problems?

Especially in larger companies today the layout in RGB is the rule rather than the exception. The advantages are obvious:

  • The layout takes place in a large, almost media-neutral color space
  • All Photoshop filters are available without restrictions
  • The process of color space conversion to CMYK is shifted to the production process as late as possible

In practice, however, there are two potential problems in particular.

Problem 1: CMYK conversion in the last step.
The catalogue is designed in InDesign, all data is perfectly matched, the last step before printing and proofing is the export to a printable PDF in CMYK. Usually this is done via a preset in InDesign, which defines the exact specifications for the color space conversion. In practice, however, this color space transfer can hardly be monitored. The problem: Even if you check the color values in Acrobat in the exported PDF file, for example, Acrobat does not really display the colors it contains. Acrobat brav would show you CMYK values even if the RGB images are still wrongly contained. However, other CMYK values can occur during printing when the data is processed again. Lately it looked like this:
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The proof is much darker than the image on my monitor. Why?

Customers are often unsettled when they hold a proof in their hands. “The proof of the picture is much darker than the picture on my monitor. Why is that so? And what do I do now?”

There are many possible reasons for a deviation between the proof and, for example, the monitor display:

  • The monitor is not calibrated
    Only calibrated monitors can accurately display color. When I buy a cheap monitor and connect it to my computer, I definitely can’t see any real color. As a rule of thumb, only a hardware-calibrated monitor has a chance for correct color.
  • The monitor is calibrated, but the colors look different
    A monitor below 1,000 Euro cannot usually be calibrated to good color representation for the standard color space ISOCoated V2, because it has a too small color gamut. Only real proof monitors are also designed and suitable for the display of proofable colors.
  • The proof is not viewed under D50 standard light
    Especially in winter the lighting conditions are often poor. And incandescent lamps, energy-saving lamps and conventional neon tubes only provide very poor colour reproduction. Without a D50 light source, a proof cannot be evaluated.
  • The color settings in the software are wrong
    Often the image editing software like Photoshop is simply installed and used without adjustments. The selected color profiles often do not correspond to the profiles used for proofing. Apple-Shift-K for Macintosh and Control-Shift-K for Windows show you your profile settings in Photoshop.

In general, no patent remedy can be given for the correct display of proofs for the monitor. However, if a proof is provided with UGRA/Fogra media wedge CMYK V3.0 and test report, the chances are high that it reproduces the required colors very precisely. If your monitor image does not correspond to the proof, the error usually lies with you. The list of causes above can help you in troubleshooting.

White lines appearing in print PDFs in Adobe Acrobat

The question often arises why when creating a PDF-X/3:2002 file in Adobe Acrobat, white lines often appear in the preview when there are no lines at all in the file.

The answer is simple: In contrast to current PDF printing standards such as PDF/X-4:2010, which is exported as PDF 1.6 standard, the PDF-X/3:2002 standard often required by printers uses PDF format 1.3, in which transparency is prohibited. As a result, when you create drop shadows in Adobe InDesign, for example, they are converted into rectangular images. If such drop shadows are still used on background images, the white lines appear, which run horizontally and vertically through the PDF at the shadow points. But why do these lines disappear in print and are not visible in other applications like MacOS Preview?

Acrobat has a preview that applies anti-aliasing to vector elements to make edges as smooth as possible. However, this setting also affects paths and masks that are not actually visible at all. The pixel images of the reduced transparencies are therefore slightly blurred. And this is exactly where the white lines of the blur appear, which are actually zero in size and therefore disappear when printed on postscript-capable printers. Not PS printers partially print the screen display, whereby the lines remain disturbingly.

Most graphic artists know the effect, have postscript printers and simply live with it. However, if you are very annoyed by the white lines or if they also appear in the printout, you can simply switch off anti-aliasing in the Acrobat preferences. Under Acrobat > Preferences > Page Display you can simply deselect the checkbox “Smooth vector graphics”. This makes the edges of vector data slightly more pixelated, but the white lines of anti-aliasing disappear immediately.

Here you can simply deselect the option "Smooth vector graphics"
Screenshot from the Preferences of the Preview in Adobe Acrobat

 

Why monitor and paper don’t get along when it comes to colour.

Colour is colour, you’d think. That’s right. But have you ever tried to explain the colour of your new car or your new red wallet to a friend on the phone? You will notice that human colour recognition and the reproduction of the same in another medium is very difficult.

The same applies to computers – better: monitors, and printers – i.e.: laser printers, inkjet printers or newspaper printing or offset brochure printing.

Why is the red on a monitor different from exactly the same red printed on paper? It’s simple: put the paper in front of the monitor. The two shades of red are exactly the same. Like this. And now you’re completely darkening the room. What do you see? The red on the monitor is still red. And exactly the same red on paper? This is black now. Why is that? Very simple:

A monitor adds light, i.e. spectral components, to the existing ambient light. If you see red on a monitor, it is because the monitor actively emits red light.

And now the paper: When do you see red on paper? Exactly when white light falls on the paper, for example through a window or a lamp. And when do you see the colour red on paper?

When white light falls on the paper and the paper extracts the non-red spectral components from the white light and reflects the red light. That’s when you see the colour red.

One colour, two completely different ways of production. And this is exactly where the colour calibration and the proof start. The strategy? Fairs. And this under fixed conditions and not with the human eye, but with “incorruptible” technology.

Put simply, a monitor calibration device can measure your monitor and see exactly “how much” colour your monitor can display, and “how wrong” your monitor can display colour. And if your computer knows that, it can correct the monitor.

Another measuring device can emit neutral white light onto a paper and measure the reflected colour. Depending on the printing process and paper, the ink looks completely different, but the meter again sees “how much” ink the print can represent and “how wrong” the print represents ink. And if your computer knows this, it can correct it. And:

If the computer knows the colour representation of the monitor and printer, it can correct and adjust the representation so that both correspond to the same colour. Of course, this only works if the colour and brightness of the light that illuminates the paper is also known and standardized.

And how does the proof work? Very simple:
If a computer also knows that the final printed product is to be printed in offset on an image printing paper, and it knows the colour representation of this printing process, then it can simulate this on a monitor and on an inkjet printer.

On the monitor, this colour-accurate representation is a so-called “soft proof”, the colour-accurate preview of the subsequent print on the inkjet printer is called “Proof” or “Contract Proof”.

This inkjet printing must be very precise and meet the highest demands in gamut and colour simulation. And since the image processing technology, colour matching calculation and measuring technology behind it is not very cheap, proofs are still mostly “expensive” inkjet prints. Due to new printing systems and inexpensive and better measuring technology, however, prices have also fallen significantly here in recent years.

What’s a proof for? The most important reasons for proofing!

  1. A proof is reassuring:
    The proof shows the colour result of the subsequent printing.
    The customer knows exactly the later result from the proof and is reassured.
    The printer knows that the customer knows the proof and is also reassured.
  2. A proof is fast:
    Ordered today, delivered tomorrow: Modern proofing service providers work quickly and produce hardly any loss of time in the design and printing process
  3. A proof is precise:
    All professional service providers nowadays work with proof printers that are recalibrated at short intervals. A media wedge with test report also provides clear metrological proof that the proof is correct and within the limits of the standard deviations.
  4. A proof is cheap:
    In the past, repro studios often charged almost 30 euros for an A4 proof. Nowadays, it only costs a fraction. Proofing costs are of little importance in the production process.
  5. A proof also shows the colors that the monitor does not show:
    In most agencies, hardware-calibrated proof monitors are in short supply. And TFTs or old tubes show colors, but unfortunately some. A proof also depicts colors that standard monitors cannot display, but which can be printed.
  6. A proof simulates newspaper as well as coated paper.
    If the same advertisement is to appear in the glossy brochure for the trade fair stand, in the trade fair news and in the special supplement in the local daily newspaper for the trade fair, then the three different colour results can be excellently simulated and presented in proofs in advance. And who knows: Perhaps the customer will then have the house brochure printed on picture printing instead of on uncoated paper due to the proof, or will choose a different motif for the newspaper ad. The proof shows it.
  7. A proof can do CMYK and more!
    Modern proofing systems can reproduce up to 98% of all Pantone colours and HKS colours in the proof.  This means that not only four-color, but also five, six and multicolor files can be proofed. Today, proofing is often done twice: once in CMYK plus corporate color in Pantone and once in CMYK and corporate color in CMYK. The client and agency can then decide whether the colour result is worth the extra charge for the fifth colour in the print.
  8. A proof is made of paper.
    Just like the product he’s simulating. A proof can be placed next to the print and compared under Normal. And to check it out, you can carry both to daylight, look at them in the candlelight and much more. A soft proof cannot do all this.

This is the first incomplete list. You know of other good reasons? We look forward to any comments and would be happy to add further points.

Which RGB working colour space is suitable for colour-consistent work?

In the early days of color spaces Apple and e.g. Photoshop up to version 5.5 set the monitor color space as working color space by default. But it soon became clear that a design office would be working with 10 Macs in 10 different color spaces. A neutral concept was needed.

There are many RGB Colour Spaces around. In the area of print media there are currently primarily three different variants: sRGB, AdobeRGB(1998) and eciRGB_V2.

The sRGB color space is widely used in digital cameras and is the industry leader in the consumer segment. Problem for printing: sRGB is a relatively small color space, and does not cover the color possibilities of modern offset printing systems and digital printers. Since offset printing profiles such as ISOCoated_v2 have a much larger color space, it makes little sense to perform retouching in sRGB.

From our point of view eciRGB_V2, a further development of eciRGB, is optimal. This color space has been specially created for use in the printing sector and offers some strengths:

  • It covers the colors of all modern printing color spaces (offset, gravure, web offset, newspaper), but is not much larger and therefore does not give away any resolution.
  • Equal shades of red, green and blue result in neutral shades of grey
  • Between 0/0/0 and 50/50/50 there is roughly the same distance as between 50/50/50 and 100/100/100.
  • The white is 5000 Kelvin and the gamma is 1.8 Kelvin.

The eciRGB_v2 color space can be downloaded free of charge from the pages of the European Color Initiative (ECI).

The AdobeRGB 1998 color space, which has been widely used by Adobe since Photoshop 5.5 and today in all parts of the Adobe product range, is also well suited for the printing sector, but works with a gamma of 2.2 and is designed for degrees of whiteness from D50 to D65. All common print color spaces can also be well mapped in AdobeRGB 1998. You can find Adobe documentation on this color space here.

 

Embed profiles for proofing? Yes or No?

The question often arises whether color profiles should be embedded in the PDF files for proofing.

To answer the question, you have to get some answers: The proof should simulate the subsequent offset printing. For offset printing, with few exceptions, the imagesetters have been configured so that a 70% black in the file is displayed as 70% black on the printing plate, no matter what profile was specified in the file. It didn’t matter whether it was coated paper or uncoated paper: 70% in the file corresponded to 70% on the plate, the choice of the paper printed on resulted in the colour representation.

The proof has also adapted to this: Most proofing service providers ignore embedded profiles, as long as the data is in CMYK and do the same as their print colleagues. Even with grayscale, the profiles are usually ignored and the grayscale is simply assigned to the CMYK black channel. Thus all CMYK and grayscale data are simply interpreted as if they had been created in the output color space. If “ISOCoated V2” is proofed, all images are treated as such, and if “PSOUncoated” is proofed, then the CMYK images are created in this color space.

This is excellent for the majority of files to be proofed. Only RGB colors contained in the data are problematic.
Since the RGB color space is considerably larger than most CMYK color spaces, it must be clear from which color space to convert to CMYK according to which criteria. Most proofing service providers specify a color space from which they convert by default if no RGB color space is defined. This can lead to difficulties: For example, many proof studios choose AdobeRGB as color space because it is large and optimized for offset printing; however, most images from digital cameras come from sRGB and these color spaces differ considerably. Therefore, it is important that the RGB color space and the rendering intend is embedded for a proof, otherwise the proofing software normally selects a color space for conversion to the CMYK color space to be proofed; and this color space is possibly not the one in which the data has be created.

Verifiability of GTIN codes in proofing

Proofing service providers are increasingly required to be able to display “verifiable” GTIN codes, i.e. barcodes in the proof.

The background to this is that especially the big german discounters like Aldi, Lidl, Hofer & Co. want to see a packaging proof from their suppliers in advance for approval. This packaging proof is not only visually assessed according to colour, but also the legibility of the printed EAN codes is evaluated using a measuring device and must meet certain criteria: Symbol contrast, modulation, decodability, defects, blemish: all this is measured and graded.

Depending on the selected setting, the GTIN lines in proofs are displayed smoother or less smooth. It is clearly visible that the modules are made up of many colours and that a considerable increase in width takes place especially within the narrow black lines. Normally a narrow black GTIN bar should correspond to the width of the white space.
Depending on the selected setting, the GTIN lines in proofs are displayed smoother or less smooth. It is clearly visible that the modules are made up of many colours and that a considerable increase in width takes place especially within the narrow black lines. Normally a narrow black GTIN bar should correspond to the width of the white space.

This involves two different risks for the advertising agency or the reproduction company that processes this data: Firstly – according to our information – in most cases the proofs are not viewed under D50 standard light, but under TL84 – the light under which the packaging will also be seen in the later sales situation. This is understandable, since the sales process takes place under TL84 and not under the standard light of a printer. On the other hand, retouching under TL84 is not mandatory, since the spectral behavior of “standard” neon means that it is not possible to produce such a reproducible and “color-accurate” result as under D50. In addition, a colour matching box with D50 and TL84 is available in very few companies, which makes it possible to view the result under both light conditions in the colour retouching.

Secondly, the proofed GTIN barcodes are measured by a measuring device and checked for their mechanical legibility. Whereas a few years ago a press proof was the standard for such tests, today mostly the digital proof is used, since it is much cheaper. But until now, the manufacturers of proofing software have always only paid attention to the representation of color, but never to the verifiability of black and white lines.

Especially with Fiery proofs, but also with GMG Color, the lines of the GTIN barcodes are usually reproduced in such a way that they correspond exactly to the black value of the required profile in terms of color, but only school grades of 3 or even 4 are achieved during the examination, depending on the discipline. Most scanner cash registers could still read and process these barcodes without problems. However, ALDI Süd or Hofer with their own GTIN codes require at least a second grade in all disciplines: The proofs all fall through the test grid of the discounters. In particular, the decodability of EAN codes has probably not been of particular importance to proof manufacturers up to now.

After detailed tests, the width increases of the GTIN bars in the digital proof and the blurring of these bars seem to be the biggest problem for the verifiability of the codes. Farbproofs.de has developed a solution together with one of the testing companies for barcodes that makes it possible to print testable GTIN codes in accordance with the strict ALDI standards, which also comply with the current proofing standards. A proof is therefore sufficient for colour matching and for checking the GTIN numbers. However, the EAN must be created and edited specifically for this purpose. This still costs far less than a conventional proof, but it is not satisfactory.  Manufacturers of proofing software such as EFI and GMG Color are therefore called upon to improve the calculation of black and white line representations in writing and GTIN codes.

Until now, the focus has always been on color accuracy, but the proof increasingly demands services that were previously reserved for proofing. At costs of 5-10 EURO for a digital proof in DIN A4 format and 150-300 EURO for a proof in the same format this is more than understandable.

An article with tips for the creation of EAN / GTIN codes for graphic designers and the problems of verifiability of EAN and GTIN codes for e.g. Aldi, Hofer, Lidl and Co can be found here.

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