1 Reply Latest reply on Nov 22, 2010 4:13 PM by MJOrts

# light representation in CS5 with xyY to LabD50 conversion or how ???

I hope somebody can help me here:

I want to represent artificial light sources on an Adobe CS5 canvas.

Artificial light sources are usually described by xy color coordinates and the luminous flux.

Lets use typical energy saving CFL (compact fluorescent, energy saving) lamps with 20 W

4000 K lamp: x=0,382, y=0,389 Phi=Y=1200 lm

3000 K lamp: x=0,457, y=0,416 Phi=Y=1200 lm

Now lets draw these 2 lamps in CS5 with the aim to illustrate the light of these 2 lamps on the monitor and in the print....and it should look similiar to the real light !

How to do this?

I have already tried to convert the coordinates xyY to Lab D50, and choosed also 1200 lm for the reference illuminant D50 and x= 0,346, y=0,359

Result:

4000 K lamp: L=100, a=3, b=22

2700 K lamp: L=100, a=22, b=56

Now I make a black canvas = night.

Next step: 2 circles with these Lab coordinates for representing the lamps.

Ok..I see that the colors roughly represent the difference between these 2 light sources..but the result isn't bright enough to represent real light.

It looks more like "pastel painting"

What can I do to get a real "light impression" for these 2 lamps on the screen?

May be I need another screen? (I have just a simple Samsung Notebook TFT screen.)

I would appreciate any suggestions or experiences.

Danuta

• ###### 1. Re: light representation in CS5 with xyY to LabD50 conversion or how ???

Hi Danuta,

I'm not sure if your monitor has enough brightness to mimic a light source with a different white point like that, but you'd also have to make sure the image is viewed in black matte full screen mode and that the monitor is the only light source in your viewing environment to prevent light adaptation.

Why do you want do this?  What do you want to use this for?