sRGB and all that

Forums Kit Chat sRGB and all that

This topic contains 10 replies, has 4 voices, and was last updated by Profile photo of wbaxter wbaxter 1 year, 2 months ago.

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  • #12258
    Profile photo of John Royle
    ajroyle
    Keymaster

    Talk of getting your colour space right in another thread,  it is surprising how easily you forget these important details when you have not printed (or had printed) anything for a few months. I had been doing some mono printing but wondered what was wrong when I printed my first colour for about three months. The print was terrible! It took a while to remember I had not reset the printer to “Let Ps control colour” after I had been using the quality monochrome setting on the Epson (it was on Colour).

    That was not particularly a colour space problem but you are asked to set to sRGB when submitting PDIs and it is important if you want to ensure that your pictures will look the same on our projector as they do on your calibrated monitor (or as near as they can ever look!). Ian M has agued, and he is right, that you may as well always use sRGB since none of your output equipment will offer much more than that anyway.

    Lr uses ProPhoto colour space only because they don’t want to impose any limitations, no amateur has any need of it nor will what they are uploading have anything like that amount of colour information!

    Always set to sRGB to send stuff to us, and then look at it set like that to be sure you are happy with it. If you forget, it is OK, our software converts it but don’t blame us for any differences. Having said that any changes will be hard to detect if it is just, say, Adobe RGB to sRGB but you can accidentally end up with all sorts of weird profiles if you are not careful and I can’t guarantee that the software will cope with everything!

     

    #12259
    Profile photo of Ian McNab
    Ian McNab
    Keymaster

    I’ve just noticed that by default Lightroom uses AdobeRGB for most purposes, but displays your pictures in the Develop module in ProPhoto RGB. (Surely this can’t be visible on most people’s monitors? But it may do unexpected things to how colours look on your screen as compared with how they print – so if you’re going to print, you must soft-proof first.)

    Here’s what Adobe says on their Color (sic) Management page:

    How Lightroom manages color

    Lightroom primarily uses the Adobe RGB color space to display colors. The Adobe RGB gamut includes most of the colors that digital cameras can capture as well as some printable colors (cyans and blues, in particular) that can’t be defined using the smaller, web-friendly sRGB color space.

    Lightroom uses Adobe RGB:

    • for previews in the Library, Map, Book, Slideshow, Print, and Web modules
      when printing in Draft mode
    • in exported PDF slideshows and uploaded web galleries
    • when you send a book to Blurb.com (If you export books as PDF or JPEG from the Book module, however, you can choose sRGB or a different color profile.)
    • for photos uploaded to Facebook and other photo-sharing sites using the Publish Services panel

    In the Develop module, by default Lightroom displays previews using the ProPhoto RGB color space. ProPhoto RGB contains all of the colors that digital cameras can capture, making it an excellent choice for editing images. In the Develop module, you can also use the Soft Proofing panel to preview how color looks under various color-managed printing conditions.

    ________________

     

    By the way, Adobe suggests that if you transfer your LR images to and from PhotoShop for ‘external editing’, it’s best to use the ProPhoto RGB colour space in PhotoShop, too, as this is what LR is using in the Develop module. Using the same colour space in both programs for this sort of exchange will preserve colour information better during the process.

    A discussion on Cambridge In Colour has this post:
    There is no option that I know of to set a color working space in Lightroom. Its native color space is Melissa, a variant of prophoto RGB. If you import a raw file, that is what it will use. It automatically translates that to make the display reasonable when you work on the image, but it doesn’t actually change the color space until you export the file as a jpg or TIFF. At that point, if you are going to display on the web, specify sRGB in the export dialog. It is sticky, so you only have to do it once. for any export setting or preset.

    #12260
    Profile photo of Peter Robinson
    Peter Robinson
    Keymaster

    Many thanks for posting these interesting and informative posts. I’ve fallen over colour profiles to my cost in the past when I had a canvas printed using the ProPhoto profile with out realising. It looked great on the screen, but was flat and dull when printed. You needed to be so careful and aware of colour profiles. I’ve just upgraded my screen is a good quality ASUS model and have calibrated it. I’m finding some of the photos I processed on my old screen now look far to light. I’ve just had a batch printed at DSC on their standard Fuji lustre paper using their profile and they’ve come out a bit dark and flat. That’s the difference between looking on the on a monitor and on a print. You’re never going to get the same vibrance.

    #12261
    Profile photo of wbaxter
    wbaxter
    Participant

    I have just changed my Lightroom file export profile to s RGB. This is done by going to Edit, preferences, external edit and then setting the drop-down boxes as you wish

    #12264
    Profile photo of John Royle
    ajroyle
    Keymaster

    When you have exported your image at RGB it is too late to make adjustments. You can use soft-proofing in the Develop module to see what will be “out of gamut” when you convert to sRGB. You can then make adjustments to the image to bring everything back – if you wish. What you then export will be fully expressed in RGB, presumably even if you get the profile wrong.

    Regarding exporting (“saving”) I just have a preset which does 1400×1050, sRGB , jpeg and standard sharpening. One click then does the saving. (I now have another, identical except for being 1600×1200 which I use at the same time)

    It is easily possible to be too concerned about actual colours, who is to know, in a single image with no knowledge of the subject, if the colours are not perfectly correct? However, having colours noticeable out of gamut will show because there will be big areas of the same colour, looking unpleasant if not downright ugly – which is why I say do the conversion yourself, don’t rely of it being OK after Dicentra has done it for you.

    People new to this – don’t worry, in a very large percentage of cases it makes little or no difference.

    #12265
    Profile photo of Ian McNab
    Ian McNab
    Keymaster

    Yes, John, that’s right: for most ordinary purposes, the color will be near enough for PDIs (largely because the projector’s default is sRGB). But Wallace’s original question  was to do with how to get a good print done by a print lab. And his workflow involves exchanging files between LR and Photoshop during post processing, and outputting a final version for the print machine at the lab. This does require an understanding of the LR + PS workflow, and the final output.

    Essentially, the outline is:

    • Import a RAW file into LR
    • Do some basic adjustments in Develop module if you wish. (LR does this in ProPhoto RGB, and you can’t alter that.)
    • Transfer to PS for detailed processing. Adobe recommends using ProPhoto RGB for two way transfers between LR and PS.
    • Process in PS in ProPhoto RGB. Transfer back to LR if needed.
    • Create the final file in PS or in the LR Print module: convert to the colour profile used by the lab’s  print  machine if that’s what they want, or to sRGB if they tell you to use that, and soft proof the result. Tweak if necessary. Export the image to a JPEG file for the lab. (The required colour profile will be embedded.)

    My solution: stick  to PDIs – preferably monochrome! 😉

    #12266
    Profile photo of John Royle
    ajroyle
    Keymaster

    I started this thread because I felt I would like to leave your entry on the other one as the last word. We have two going which are very similar and I hope very helpful. In the case of printing the output must be in a suitable colour space, though we are saying you are safe with sRGB. You could also, of course, soft proof in Lr to match whatever your paper or commercial printer’s requirement is too, as you say. I usually take a quick look but if there are just tiny areas showing as out of gamut I leave it. Naturally this also applies if you are getting  prints done elsewhere, if RGB is the required profile then you can check if your final image is “in gamut”.

    I agree too about printing out of Lr, I’ve not used Ps for serious printing for a long time.

    I would not do as Wallace has done and just commit to sRGB routinely.

    #12267
    Profile photo of wbaxter
    wbaxter
    Participant

    You keep using the term ‘Soft Proofing’ how do I do that in Lightroom or PS? Is there a soft proof button?

    #12268
    Profile photo of Ian McNab
    Ian McNab
    Keymaster

    You keep using the term ‘Soft Proofing’ how do I do that in Lightroom or PS? Is there a soft proof button?

    In LR, it’s in the Develop module, under the View menu > Soft Proofing > Show Proof. (You have to have chosen a colour profile for the image already)

    In Photoshop (as far as I understand – John may be able to advise further) it’s a bit more complicated. There’s an explanation here:

    http://www.colourphil.co.uk/photoshop-proof-colour.shtml

     

     

    #12274
    Profile photo of John Royle
    ajroyle
    Keymaster

    Thanks Ian. Wallace, I can do no better than recommend the excellent video by Julieanne Kost. It is the first thing I saw about soft-proofing in Lr and it is old, but nothing has changed (ostensibly) on colour proofing since this was made.

    Julieanne Kost – Soft Proofing

    As I have said, I don’t soft-proof in Ps, but here is the Adobe video on it.

    Oh, and even if you stick to PDIs, as I’ve said, you can softproof for RGB output, so you know how the colours are going to look.

    Lastly – that health warning again – Nobody is going to notice if colour fidelity is a bit wrong in a single image and you may have been chugging along happily for years doing what you do and feel you don’t want to bother with all this, but if you are not quite happy with the colour of an image this is something you might try if you already have a calibrated monitor.

    #12275
    Profile photo of wbaxter
    wbaxter
    Participant

    Thank you both John and Ian, have now watched the lovely Julieanne, and followed her instructions and successfully soft proofed the image I had the problems with at DSC labs.

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