Hi Chris, On 2014-07-17 10:13, Chris Lilley wrote:
Firstly, the rendering intent used for gamut mapping is not discussed. When a wide gamut image is reduced down to a very small one, relative colorimetric tends to keep the in-gamut colours the same and piles up all the OOG colours at the boundary to give flat areas where there used to be gradients. Perceptual, aka do something magic and undefined, tends to map the entire source gamut to the destination gamut in a content-unaware way which results in significant and needless desaturation.
But that is irrelevant for the topic of whether to keep stuff wide till the end or convert to small at the beginning. The conversion will have to happen anyway. The question is, where do your losses happen or where is the bigger chance that you loose something in your path from camera to output. And it also depends whether the tool chain you use even allows that selection.
Export from Lightroom or AfterShot for example is hardwired.
Well, in all practicality, there are only a few image editors out there that can handle more than 16bits, so it becomes theoretical issue.The second thing that is missing is an examination of whether 16 bits per component is actually sufficient for ProPhoto. It isn't, really, for Lab and it needs to be shown, rather than assumed, that 16 bit is sufficient resolution for ProPhoto.
I rather stick to practical stuff I can test empirically. And it is so easy, even with a $100 toy printer (and appropriately profiled paper) to see that staying wide 'till the end gives the most realistic rendering of saturated colors.
Some words on the gamut of your printer, and links to the various profiles used, would also round out a nicely argued article.
Yup, it is somewhere on my todo list. cheers afx -- http://afximages.com/