Re: [Lcms-user] Looking to translate values between two ICC profiles

[<mar...@li...>]

Hi Spencer,

This may be easy, but still I don't fully understand what you mean  
with "value inputs from different input profiles". If this means  
different combinations of RGB numbers, for example (10, 20, 30) (128,   
128, 128)
and so, then it is quite easy to solve:

Using your favorite image editing app, create a tiff file with patches.
Use each RGB combination you want to check for the patches. Save the  
tiff file as untagged, don't embed any profile. This will be a  
deviceRGB only file.

Then use tifficc and specify the profile you want to check as input  
profile. The default output is already sRGB

tifficc -i <put here the profile name> tiff_device_rgbb.tif output.tif

In output.tiff you will get the sRGB equivalents, *but*

- Colors out of sRGB gamut will be clipped, you may want to use  
perceptual sRGB V4 profile for better out of gamut handling.

- I don't see any practical application of that anyway.

In the other hand, what you probably want to do is soft proofing. This  
can also be done with tifficc, but is a little bit more complex:

Create a L*a*b tiff with patches of intended *colors*. Lab tiff has  
huge gamut and can cope with whatever. If lab tiff cannot contain a  
color, then neither ICC profiles. Note that I say colors, since Lab is  
colorimetric. An Lab value does specify a color, an RGB value does not.

Use tifficc softproofing feature. -p  <profile> and -m <intent>, this  
would give you the color appearance in sRGB space. I guess this is  
what you really intend to do.


Hope this helps
Marti

Quoting Spencer Delamore <sde...@co...>:

> Hello all, I was hoping someone might be able to help me figure this out.
> I'll explain what my goal is; I'm trying to take different color  
> value inputs from different icc profiles(stock profiles and  
> eventually uploaded personal profiles) and be able to output usable  
> sRGB values to make a swatch from(using ImageMagick). I'm using the  
> command line managed by php. Maybe I should just use imagemagick to  
> do everything, since I think your lcms is part of it anyway? The  
> swatch part is taken care of, I'm just looking for a way to convert  
> data inputs from one profile into data points of another profile.  I  
> was trying to do with with the transICC tool in LCMS, but I came to  
> realize that the tool only shows the differences, when I need to  
> find a translation.
> I'm sadly, not vers in C, working with this through the CLI.
> Thanks guys! Any help is greatly appreciated, 
> -Spencer