The CRI (Colour Rendering Index) is a measure of the colour rendering quality of a light source. It indicates how well a light source reproduces the colours of objects in comparison to a reference light source, e.g. a daylight spectrum.
The colour rendering index is measured on a scale from 0 to 100. A value of 100 means that the light source reproduces the colours of objects perfectly. A value of 0 means that the light source does not reproduce the colours of the objects at all.
LED lamps usually have a CRI of 80 to 95, which means that they reproduce the colours of objects well. However, LED lamps with a colour rendering index of 100 have recently been introduced by manufacturers such as YUJILEDS and are particularly suitable for use in areas where the quality of colour rendering is important, e.g. in photo studios or museums.
In the printing industry, D50 standard light is the common standard light in Europe. Whether you need D50 standardised light depends on your requirements. If the colours of objects and prints need to be reproduced very accurately, D50 standard light is the best choice.
However, if the requirements for colour rendering quality are not so high, an LED with a high CRI can simply be used. LED lamps with a high colour rendering index are generally cheaper than D50 lamps and easier to find.
At Proof GmbH, we have standard light booths from Just with D50 standard light, but we often only use an LED with 500 Kelvin and the highest possible CRI of 90+ on the winders. Nevertheless, significant colour differences and metamerism effects often occur here when proofs are only viewed on the cutting table. We therefore always use the standard light booths for a comprehensive colour assessment.
Unfortunately, no retrofit solutions are currently available for simply replacing ‘old’ D50 standard light neon tubes with LED tubes, for example. As neon tubes will be banned from 2024, completely new LED units must currently be purchased and installed from Just, for example, when replacing old D50 standard light neon tubes. However, at several thousand euros, the replacement is currently still quite expensive.
More articles related to this topic:
Proof.de: New video online
In this short image video we – the Proof GmbH – introduce us and our work. Find out who we are and what drives us. What do you think of our short film?
New edition of ISOCoatedV2 in M1 in sight?
Even almost 9 years after the introduction of the successor colour space PSOCoatedV3, ISOCoatedV2 / FOGRA39 is still the most widespread colour space in Europe. We at Proof GmbH count around 200 jobs from time to time for the German Printing and Media Industries Federation, among others. In the last count, proofs in ISOCoatedV2 accounted for around 68% of all proof jobs at our company. This is a clear sign of the continued widespread use of the colour space. ISOCoatedV2: From the classic colour space to the beacon of the … read more
Incorrect grayscale display in Adobe Photoshop and InDesign
Adobe products are ideal for image retouching and layout and handle RGB and CMYK colour profiles very well. However, when editing and retouching grayscale images, for example for a black-and-white photo book, the experience is quite different. Suddenly, images look completely different in InDesign than they do in Photoshop, and even when exporting the image to PDF, greyscale images are suddenly treated differently. This article explains where the problems lie with black-and-white images and greyscale profiles in InDesign and Photoshop layouts, and how you can work in a more ‘colour-accurate’ … read more
We passed the first proof certification for the 7C proof under FOGRA55
A few days ago Proof GmbH was the first company to be certified for proofing for the new 7C exchange colour space FOGRA55. Fogra has developed characterisation data for extended multicolour printing with the printing colours CMYKOGV – i.e. cyan, magenta, yellow, black (contrast), orange, green and violet – FOGRA55 as part of a research project over the past few years. The characterisation data and the ICC profile Ref-ECG-CMYKOGV_FOGRA55_TAC300.icc have been published on the Fogra website in recent weeks. We have now carried out the certification via GMG ColorProof, as … read more
Proof.de is featured twice in the “Fogra Aktuell” magazine
In the current issue of Fogra News “Fogra Aktuell” Proof GmbH is involved in two places. Firstly, a summary of the Fogra report on our first FOGRA55 certification for seven-colour printing with extended colour space in CMYKOGV appeared. You can also find more information on our FOGRA55 certification on the Fogra website: https://fogra.org/en/press-releases/fogracert-erste-cpc-zertifizierung-fuer-fogra55-cmykogv-330 and on proofing.de: And secondly, there was a report on the completion of the research project for textile digital printing, FOGRA58, in which we were allowed to investigate and test the proof capability of the new textile … read more
New feature: Orders & individual items can now be reordered with a single click
From now on, it’s much easier and faster: in the Proof Shop, you can call up and reorder entire orders or individual proofs directly from your order history. This saves you from having to re-enter every detail and gives you the assurance that all settings will be exactly the same as last time. With just a few clicks, your proofs are reordered – reliably, easily and in no time at all. What exactly is new? You can find your order history in your customer account. There are two new options … read more
RGB colour spaces explained
RGB colour spaces are colour systems that represent different hues with the three primary colours red, green and blue. RGB colour spaces are used in digital image processing, photography and computer technology to precisely define colours. The most important RGB colour spaces and their special features are: sRGB sRGB is the most widely used RGB colour space and is used by most monitors, printers and digital cameras. It was developed by HP and Microsoft in the 1990s to create a standard for colour representation on the internet and on various … read more
Precise proofing of tonal values of spot colours
In recent weeks, there have been lengthy discussions on the Fogra digital printing mailing list as to whether a research project should be launched to define standardised tonal value gradations for spot colours. What is this all about? In the field of CMYK and seven-colour printing, the definition of clear, printable and proofable standards is well established and has been tried and tested in practice. If the paper or paper class is known and defined, a measuring standard such as M0/M1/M2 has been established and the content of optical brighteners … read more
New PANTONE Formula Guides with incorrect ink formulations
Several errors have crept into the new PANTONE 2023 fan decks. In both the PANTONE Solid Coated and the Solid Uncoated color fans, there are colours for which the new ink formulations are incorrect. In the PANTONE Formula Guide Solid Coated fan 2023, PANTONE 107 C and PANTONE 108 C have absolutely identical ink recipes, as well as PANTONE 113 C and PANTONE 114 C. As the colors differ, this cannot be the correct. Several errors in the PANTONE Solid Uncoated fan 2023 In the PANTONE Solid Uncoated fan 2023 … read more
New iPhone colour measuring devices: xade nano+ in test
A new generation of colour measuring devices is entering the market: in contrast to the classic measuring devices, which are available as a fully encapsulated system either as a colourimeter or as a spectrophotometer, and then supply the data to a computer via an interface or app or display it directly, the new generation of colour measuring devices consist only of lighting and software, with the optics of a modern iPhone from Apple being used as the sensor. Until now, there have been two categories of measuring devices on the … read more