Why M2?

There are a couple of reasons why M2 is a dominant M-condition for ChromaSpot Color Library:

  • More and more lighting today is LED-based and has no UV. 
  • Production of fluorescent tubes is limited to recycled mercury only. It will go down near to zero shortly.
  • Perception of the color depends on invisible hard to measure UV component
  • The industry still has a problem with OBAs and proper ICC profile creation based on M1
  • Most of ICC Profiles for Large Format and Digital are M2
  • OBAs are unstable - the paper is losing OBAs, and the initial white is fading.
  • Fluorescence is not standardized correctly across different instruments
  • Most of the paint color libraries are M2-based
  • UV is harmful, and there should not be pressure to use it. 
  • Instruments are described and calibrated based on BRCA standards - ceramic tiles with no OBAs. 
    The inter-instrument agreement is quantified based on M2 standards only; fluorescence measurements are not inlined in practice.
    There is no standardized way to compare how two instruments measure M1-M2 or M0-M2.
  • Most color libraries also use M2 data to create color libraries for design software (Adobe, Corel, ...)
    Most designers use M2 color coordinates for design.
  • A new upcoming P3 viewing condition (D50 noUV) for the ISO-3664 standard is under development.

Where is the problem with M-conditions?

Most users don't understand the impact of OBAs and UV - both elements are invisible, so this problem is often ignored.
Most paper manufacturers use OBAs to achieve the illusion of perfect white, but that will probably change as more LED lights do not activate the fluorescence phenomena of OBAs, and ideal white becomes greyish or yellowish. The industry and market must change and reject the use of OBAs.  There is no sense in adding UV to LED lamps - as UV is harmful and will increase production costs.

What are the consequences?

While we selected M2 as a dominant M-condition, the coding convention uses M2 data to calculate Lab coordinates. In the case of M1, that may confuse some users, especially for neutrals and near-neutral grays. Chromaspot is created using samples printed on the substrate that contains a medium amount of OBAs. Samples that are almost perfectly neutral in M2 data become blueish when switched to M1 or MO. If you are looking for neutral samples in M1, use the Lab or LCH tool to find them. In such cases, whenever LED or other light source with no UV is used to illuminate M1-neutral samples, it will be perceived as yellowish...

If you use M2 color coordinates and the substrate contains OBAs - depending on the amount of UV components in the light, the perception of color may dramatically change. 

Want to learn more?

Do some simple exercises - that should help you understand the OBAs/M-Condition issue.