on landscape The online magazine for landscape photographers

David Clapp Webinar

Soft Proofing for Web Output

Tim Parkin

Tim Parkin

Amateur Photographer who plays with big cameras and film when in between digital photographs.

Flickr, Facebook, Twitter

Firstly we’d like to give a big thank you to both our presenters and panelists, David Clapp, Tim Parkin and Neil Barstow and also everyone who signed up for the webinar - we initially advertised it as for 16 people but in the end we have over a hundred registrations and in the end eighty four people turned up.

We recorded the but skipped the introductions - we’ll include them next time - but the one thing that wasn’t recorded was the questions so we’re addressing some of the issues raised in the notes below and will look at writing articles addressing just these issues in a future issue. We refer to David's original presentation in the video and you can find that here.

and here we expand on a couple of the questions raised from the webinar

This is a premium article and requires a paid subscription to access. Please take a look at the subscribe page for more information on prices.
  • Rennie

    Thanks for the video. Now I know why my sRGB images don’t look as good as my prints and why some prints just look flat and lack highlight detail. The only problem remains how to recover them . An interesting point remains that my custom print profiles seem to have a slightly wider Gamut (red/yellow)than RGB. I will need to do some prints to see if this is an anomaly. Ken

  • A very interesting watch gents, thanks very much. Many good points and lots to ponder.

    I think Rob Knight asked a question about managing proofs within Lightroom. When you are in softproof mode you should see a ‘Create Proof Copy’ button underneath which will essentially create a virtual copy that you can then make any proof-specific edits on. The filename displayed in the info will show the profile used for the proof so you can keep tabs, and you can stack it with the master copy.

    As I understand it’s not much more than a virtual copy but tagged with the profile in question. It would be nice if you could have a proof copy that just has relative adjustments to the master copy so that they stayed in sync rather than perhaps becoming completely different interpretations or duplicating effort if you chose to change one.

    However given that David showed how relatively blunt LR’s tools are in dealing with gamut issues, it’s perhaps less useful anyway as you’d probably want to make the adjustments in PS instead.

    Regarding the ‘losing data’ point raised in questions and addressed above, I don’t believe you ever ‘lose data’ in the strictest sense. The same data is represented in the binary image file regardless of the profile assigned. When you assign a profile it’s more telling the display device how to interpret and represent that data, rather than changing it. You can see that the image data is intact by assigning ProPhoto, saving, then changing to sRGB, saving, and then back to ProPhoto and saving. At each stage the file size is unchanged and the image will look the same in the end.

    Of course the point is that you’re losing the ability to use/display/print certain colours if the profile is wrong but you shouldn’t worry that you are in some way damaging your source file by changing from a larger to a smaller colour space.

    Or if I’m wrong, please do correct me! :)

    • Hi Duncan – thanks for the comment! We’re just getting into webinars so we’re delighted our first attempt has had the right effect. The virtual proof copy in Lightroom is quite cool – I need to look at it in a little more depth. The idea of relative adjustments is a nice idea but as the rendering intents don’t scale linearly (particularly perceptual) I’m not sure they will be as useful as appears at first glance.

      As for ‘losing data’ when you use different profiles. The answer is ‘it depends’; and it depends on a couple of things.

      1) What is the profile that gets applied when your raw file is converted and how is it applied

      2) How big is the gamut of your picture after this step relative to your proposed exported colour space.

      Essentially you can apply a camera neutral profile and end up with a very subdued image that doesn’t exceed any colour profile gamuts and hence most transformations will not lose data.

      It’s also possible that a camera profile may create such a garish representation that the colours exist even outside of MelissaRGB and hence you will lose data when the photo is imported into lightroom (although lightroom always works on the raw data so you can change the camera profile at any point in time). The most obvious way you can lose data is by clipping the colour space when you export to photoshop for instance.

      e.g. Take a garish picture in MelissaRGB (a ProPhoto size icc profile) and export to Photoshop in sRGB and then when you’re in Photoshop convert it back to ProPhoto. The colours will have been clipped and you will have ‘lost data’.

      [techy bit: Actually, you also can lose data when you convert a very monotone picture into ProPhoto as all the data points have to be reduced in value to fit within ProPhoto. This is pretty irrelevant for most uses though as long as you’re working in 16bit because most cameras are only 12bit.]

      Hopefully I can write more and make more sense of this in a future article..

      • Good point re: rendering intent.

        Re: data loss. Hmm, yes, looks like you’re correct (of course)! My (false) understanding was that the assigned profile didn’t change the colour data itself, it just described how to interpret that data. E.g. if you had a file with pure red RGB(255,0,0) but maybe sRGB can only manage say RGB(240,0,0) I expected the data in the file would still be RGB(255,0,0) even with an sRGB profile and it was downshifted/clipped at display time, i.e. anything north of RGB(240,0,0) would just display at the same value.

        But having run your test you’re quite right. What I did was:

        – take a nuclear sunset with +100 saturation (I’ll post it to Flickr later! :))
        – softproof using sRGB – lots of gamut warnings!
        – export as 16bit sRGB
        – open in Photoshop, convert to ProPhoto, save back out
        – import that file into Lightroom
        – softproof again using sRGB – barely any gamut warnings. Big patches of yellow that were giving warnings originally are the same slightly lighter shade of yellow with no warnings.

        Interestingly bringing the sRGB file back in and softproofing against sRGB still shows some gamut warnings. Much reduced, but still there which I wouldn’t expect?

        So yes, it looks like you do lose data and that when you assign the profile it does translate (downgrade) the out of gamut colours to the closest in-gamut. My previous testing was flawed because of course the file size won’t change as you still have the same number of pixels represented by a 16 bit value – it’s just that the value of each data point has been reduced to fit within gamut!

        In my head it made more sense that the profile would be used to translate but that would require an extra processing stage each time you opened an image file and just make displaying an image more work than it should be. Oh well.

        Ok, lot of technical stuff, sorry if that didn’t make sense. Upshot is, stick with a suitably large colour space whilst working on an image (I always use AdobeRGB).

        Thanks again Tim/David, good stuff to work the brain matter! :)

        • To add, I did another experiment by exporting an image twice as a TIFF – once using ProPhoto and again using sRGB. File sizes are the same (obviously, heh!). I then opened them both in a hex editor and diffed them – the entire contents of the file were different. If my original thinking would have been correct, it would’ve just been the ‘profile’ data in the file header that would’ve changed. So ye, the data is being changed by the profile as you say.

  • Marc Elliott

    Hi David. I really enjoyed this, and gained a lot from it. I hadn’t paid too much attention to the colour elements of the histogram before, or even considered gamuts and different colour spaces. Colour control has always been a bit or miss for me. but now feel by checking for within gamut at the start, is a good point to begin assessing the pictures colour. As well as hue&sat adjustment layer, I found using gentle adjustment of a curve channel worked also for bring a colour back within gamut. Thanks again David and Tim for another brilliant tutorial.

  • David Higgs

    Isn’t black and white great :-)

    seriously though, that’s an excellent start to these webinar events

On Landscape is part of Landscape Media Limited , a company registered in England and Wales . Registered Number: 07120795. Registered Office: 1, Clarke Hall Farm, Aberford Road, WF1 4AL