Hi :)

Kevin Gale wrote:

> Our application scales RGB digital camera images to specific sizes using 
> Bilinear scaling. We are investigating adding support for the embedded 
> profiles using lcms.
> If I am making the image smaller I will be able to get better performance by 
> applying the destination profile after the scale. If I am making the image 
> larger I will be able to get better performance by applying the destination 
> profile first.

Yes, and yes.

> Are there any rules for this (such as always transforming first no matter if 
> I am making the picture larger or smaller) or does it not really matter?

One thing to bear in mind is that the interpolation (or averaging) 
involved in scaling an image is affected by the gamma of the colourspace 
in which you're scaling.  For work in which no error at all can be 
tolerated, scaling (and most other manipulations) should be done in 
linear space, with gamma removed.  In practice, however, the effects of 
this consideration are relatively minor, and since colour-transforms are 
computationally expensive it generally makes sense to apply them to as 
few pixels as possible.

All the best,
--
Alastair M. Robinson

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