Update: The original aim of this article was my attempt to highlight how different colour spaces look on phones & tablets, prompted by some personal disasters I'd experienced! Although my eventual conclusion is still correct - always use sRGB for anything viewed on the internet - and my example images demonstrate it very well, some of my original thoughts and musings were incorrect! I've left the bulk of the blog post intact but corrected some of the worst errors. My thanks to Mark Wycherley for a comprehensive lesson in colour spaces!
Recently I have been finding that some, but not all, of my images shared online were looking very different on phones & tablets when compared to how they look on computers. The problem was happening very frequently but not always consistently so I set out to investigate. I've now narrowed it down now to the colour spaces I've been using, both when shooting and then later when processing in Lightroom & Photoshop. The underlying reason why my images were looking washed out and pretty awful when viewed on any kind of mobile device I tried was ultimately because my images were exported in the ProPhoto RGB colour space. It was this colour space the mobile devices were struggling with.
I'm not going to go into a full explanation of colour spaces here but this wikipedia article is very comprehensive!
For the last six months or so I've been deliberately shooting in Adobe RGB on my Canon 6D & Fuji X100S. The main benefits to me are similar to the reason I was shooting in RAW even before I really knew how to properly process a RAW file - I think it's better to keep the most data we can from our photos, even if right now we don't need to make full use of it. "Surely it's better to be future proof?", I thought!
However I observed that after I uploaded these images to social media or photo sharing sites like Flickr they looked noticeably different on any tablet or smartphone (regardless of brand). For quite a while I actually thought it was Flickr or Facebook changing my images because the effect was exactly the same regardless of whether I shot on the 6D or the X100S and I was shooting in different colour spaces on each camera.
The fact images with different colour spaces render very differently may not be news for some but it was a big surprise for me. I expected there may be some slight differences but after comparing the same image exported across all of the most common colour spaces the differences are pronounced. Aside from the images exported in CMYK, all of the images look essentially the same on any monitor I've tried - it's only on phones/tablets that they look different. To show how they render differently I exported actual screen dumps for each image.
Take a look at the samples below to see for yourself. All of these were shot on the 6D with ProPhoto RGB as the default in-camera colour space then exported from an iPhone 6.
As I said earlier, it may not surprise you to learn that different colour spaces are rendered differently on mobile devices. I expected some subtle changes but nothing quite so pronounced. The solution seems simple - either shoot in sRGB or remember to convert the profile to sRGB during processing.
What surprised & confused me though was when I noticed the same thing happening to images shot on the X100S... That camera only shoots in sRGB and Adobe RGB but it was as though my images were somehow coming out as ProPhoto RGB in some cases and Adobe RGB in others.
However, if you pull your image into Photoshop it seems to be automatically converting the colour space to ProPhoto RGB. Same image, shot on a camera that cannot output to ProPhoto RGB but something in the "Edit in Photoshop" process has chosen the new colour space.
*update* - by default Lightroom's Develop module works in ProPhoto RGB and exports JPGs in AdobeRGB. Remember to change to sRGB for online usage.
This is why I was seeing issues with most images but not all. When I didn't feel the need to use Photoshop, images are exporting from Lightroom in Adobe RGB mode which looks more similar to what I see on my monitor. It's only when the image was pulled through to Photoshop - which I do with a sizeable percentage of the images I like the most - then it's saving down as ProPhoto RGB and the results render very badly on mobile devices.
The moral of the story? Always be aware of the colour space you're working in, especially when moving between applications. Be mindful what each of the different options look like, not only on your monitor but on mobile devices too.