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.
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
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
Over the last few months, we at Proof.de have been thinking about further improving our already very good colour measurement technology in terms of speed and measurement precision. Relatively quickly it became clear that only two devices would come into question: The KonicaMinolta MYIRO-9, the successor of the former FD-9, or the X-Rite ISIS 2 XL. The starting point: Since we at Proof GmbH have 5 proofing devices, the calibration of targets for profile optimisation is a time-critical undertaking for us. Therefore, we had been looking around for an upgrade of … read more
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?
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
Peter Jäger is an expert in colour management that reliably works across the boundaries of printers and monitors, web and print – essentially: cross-media.
Anyone who has reinstalled or updated their i1 Profiler app in the last few weeks has been confronted with disturbing news: X-Rite announced directly in the start window that it would no longer support its enormously popular i1Display and i1Pro2 devices. Users of the i1Pro 2 devices and i1iO 2 tables, which are extremely popular in printing and colour management, will be particularly hard hit by the announcement: An investment of €6,000 is quickly consigned to the electronic scrap heap. But what can you do if you own such a … read more
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
In recent years, various problems have arisen with our previous proof paper supplier. On the one hand, we sometimes had to wait more than three months for paper deliveries; on the other hand, we sometimes had significant problems with batch-to-batch discrepancies, surface defects and much more. After lengthy deliberations, we decided in December to replace all the paper. We therefore received pallets of new paper at the turn of the year, which we are now gradually incorporating into our production. There will be no hard cut, but the new papers … read more
In 2021 proof.de was again Fogra certified including Fogra “Spot cert” certification, i.e. for the display of spot colours such as PANTONE C and U.