CHROMiX

Paper / Monitor correlation using lightbooth

Hi all,

I am new to this forum so plz excuse if I am breaking any rule, I’ll try not to.

Here is my point :

I’ve read all the posts relating to light booth / monitor white point correlation.

Still I can’t help thinking that this is totally weird and non-user-friendly to set a monitor whitepoint to D65 in order to achieve correct soft proofing under calibrated D50 lighting.

My setup is a EizoCG275 and a colorcommunicator2 from just-Normlicht. I do profile my Hahnemhle papers using a X-Rite i1Pro2 with standard D50 settings and M0 UV included.

I would expect such an expensive setup to be user-friendly & work fine out-of-the-box… well not.

Am I missing something ?

I’d really appreciate some color-guru to provide me with an in-depth explanation of this matter.

Thanks a lot in advance

Laurent LORETTE

The reason is written, for example, in the book “Color Appearance Models” by Mark D. Fairchild, Wiley. I copy and paste these paragraphs from page 159 of the second edition:


When hard-copy images are being viewed, an image is perceived as an object that is illuminated by the prevailing illumination. Thus both sensory mechanisms, that respond to the spectral energy distribution of the stimulus, and cognitive mechanisms, that discount the known color of the light source, are active.

When a soft-copy display is being viewed, it cannot easily be interpreted as an illuminated object. Therefore there is no known illuminant color and only sensory mechanisms are active.

This can be demonstrated by viewing a white piece of paper under incandescent illumination and comparing the appearance to that of a CRT (or LCD) display of a uniform field with exactly the same chromaticity and luminance viewed in a darkened room. The paper will appear white or just slightly yellowish. The display will appear relatively high-chroma yellow. In fact, a white piece of paper illuminated by that display will appear white while the display itself retains a yellow appearance!

Regards

Mauro Boscarol

Oooh Mauro, what a beautiful explanation and way of explaining how/why chromatic adaption occurs and even some real world examples of it in action.

I know it wasn’t your answer, but what an excellent quote all the same.

Hi Laurent,

I agree… it is weird. The only thing I can say in its defense is that it seems to work. To match a D50 illuminant, a display should be calibrated to be somewhere near D65. But it can vary a bit. I always recommend that people try the white paper test. Put a blank piece of your white Hahnemuhle paper in your viewing booth and compare that to a blank white document in Photoshop. Enlarge it so it fills the screen. Adjust your monitor calibration settings until the monitor white matches the viewing booth.

As Fairchilds explains, our eyes see reflective light (out of the viewing booth) differently than they see emissive light (from the display). So for one thing, it’s actually hard to compare the two - our brains have a hard time doing that - even though it seems to be simple enough, it’s just two samples of white after all.

Then there is something about how our eyes interpret color differently at lower luminance levels. I understand that in a press-side setting, a monitor and light booth will both match at D50 because the luminace of both is much higher. However, in the home office photography-type settings that we’re generally talking about here, the brightness of these environments and the luminance of these devices is much lower and you have to move the display closer to D65 to get the match to work.