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Author Topic: Why is it recommended to export as sRGB for jpeg?  (Read 8146 times)

digitaldog

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Re: Why is it recommended to export as sRGB for jpeg?
« Reply #20 on: August 21, 2014, 10:19:58 am »

Thanks that was very helpful. I'll probably try the easy method, since the hard method is out of my expertise at the moment.
Here's the deal. Ask yourself why you're moving from a nice wide gamut image to sRGB. Probably to post the image to the internet. Short of being forced to send to some lame lab that is cluless about color management, it is for web or screen viewing. If for the web, all bets are off in terms of what other's see of the image. Are their browsers color managed? Is the display calibrated? Is it a nice new Eizo or NEC or a 16 year old CRT? It's a crap shoot. While I believe we should make our images look as good as possible, is it worth the time and effort to muck around for conversion to sRGB to be posted to the web? Only you can answer that.

Having to resort to showing images on the web and expecting everyone see the same quality you do is like being stuck hungry in an airport with a 5 hour layover and only have the choice of KFC or McDonald's. 
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yalag

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Re: Why is it recommended to export as sRGB for jpeg?
« Reply #21 on: August 21, 2014, 11:20:29 am »

Note that you are saying "OFTEN produces better results" and "PROBABLY yield a worse result".  So one question to consider is what probability do those qualifiers represent.  Is it >50% of the time, >80%, >95%, or >99.9%?  Personally, I would have no problem believing the >50% and probably not much of a problem with the >80% either but I would start questioning probabilities much higher than that.  I see plenty of pics on the web of red, yellow, and orange objects where the photographer just let the rendering intent do its thing and they look pretty bad.

The other variables that come into play are how perfect you need your image to be and how much time and money you are willing to spend to get it there.

So ultimately I think you need to be your own judge and to use your eyes to the extent that you can, with soft-proofing, test prints, and so on.  Whether you are using relative or perceptual rendering intents, or you are doing your own tweaking to bring colors into gamut, you want to be looking for hue shifts and detail loss and making sure those compromises, if any, are acceptable to you given your time and money constraints.

I'm just looking at it from an theoretical point of view as it's about education at this point more than practical applications. In practical terms, I would imagine it probably depends on a lot of things. The image itself, how far off is it out of gamut etc.

Theoretically, almost every course I have watched now recommends some kind of workflow where you would edit the photo during soft proof. But if >50% of the time, the editing puts you in a worse position, I think this should be warned or explained. It's not even an edge case.

One of these courses is Andrew's own color management with photoshop cc. I see that in his video, he carefully avoided the saturation adjustments and stuck with contrast and hue only. While many other courses recommend that you tone down the saturation. In fact adobe's own video does this! I really don't see this being a good idea unless you have a very specific image where pulling down the saturation of that color only have a very localized effect. Otherwise you'll almost always end up with a crappy image.

I guess one day if they come up with color control only for out of gamut colors then that would be a good workflow?
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Royce Howland

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Re: Why is it recommended to export as sRGB for jpeg?
« Reply #22 on: August 21, 2014, 11:58:36 am »

[...]I guess one day if they come up with color control only for out of gamut colors then that would be a good workflow?

I think that's a bit too simple of a solution. The best solution will vary based on the image itself, and the goals of producing the output. We have two common rendering intents that handle out of gamut colours in different ways: perceptual compresses the whole gamut to preserve subtle details at the expense of lesser overall accuracy of colour; while relative colorimetric preserves overall accuracy at the expense of clipping out of gamut colours thus wiping out detail. Sometimes one approach is okay, sometimes the other is better. It depends.

In the same way, if you chose to do manual work in post to adjust the image prior to letting the rendering intent tackle things, sometimes you might want to bring down only the out of gamut colours. Other times you might want to bring down a broader range of colours including some that are in gamut, in order to preserve subtle surrounding details and "feather" the adjustment more gracefully.

When I do these kinds of edits, saturation usually is the last adjustment I resort to. I usually start with tonality adjustments in one form or another -- curves, luminosity. Or other types of non-saturation adjustments like hue or density tweaks. The adjustments I make are guided by soft-proofing initially, but not by soft-proofing in Photoshop for cases I really care about. If I really want to see what's going on, I use Gamutvision (a Windows tool) which provides more comprehensive, detailed and useful information about differences between image colour and rendered output colour.

Whatever types of adjustments I'm using, I would rarely-to-never hit the entire image with a global adjustment. Typically I would make changes in selective regions (including specific channels) of the image, but covering a somewhat broader range of colours than just those that are strictly out of gamut. I'm usually trying to strike a balance between detail and colour accuracy; where I put the fulcrum for achieving that balance may vary from one image or output purpose to another.

And of course, like Andrew says, I don't go to this effort for any images I post at low res to the web. Those cases just aren't worth it. When I tackle this issue manually, it's for prints that I really want to dial in.
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