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teenas96182878
teenas96182878
Participant
March 23, 2021
Answered

Out of Gamut Fixing Question

  • March 23, 2021
  • 3 replies
  • 3132 views

I am trying to prep artwork for print on demand and have watched several videos about fixing out of gamut color but I am still not clear on if what I am doing is correct. The photo I am practicing on is my artwork of a weathered blue door, a weathered porch and then a red/gold hound on the porch. (See photo attached.) The out of gamut colors are on the door facing and door for the most part and I changed those gray colors to magenta so I could see them better. Several tutorials gave several different explanations of how to fix. One suggests creating a new adjustment layer and changing the the saturation in that layer, but when I do that and get rid of all the out of gamut magenta color, it washes out the rest of the color. Another tutorial suggested that a better way was to using edit preferences, transparency in gamut and then choosing to lighten the chosen color of blue which I am selecting but that seems to wash out the enter picture. Maybe both of these are okay because it's a masked layer but I am not sure about the results I am getting. The image certainly looks washe out. Does that sound like the right result? 

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Correct answer davescm

Ok. Thanks

--
Teena M. Stewart

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Hi

see if this helps your understanding of color spaces and their associated colour profiles :

 

Digital images are made up of numbers. In RGB mode, each pixel has a number representing Red, a number representing Green and a Number representing Blue. The problem comes in that different devices can be sent those same numbers but will show different colours. To see a demonstration of this, walk into your local T.V. shop and look at the different coloured pictures – all from the same material.

To ensure the output device is showing the correct colours then a colour management system needs to know two things.

1. What colours do the numbers in the document represent? 
This is the job of the document profile which describes the exact colour to be shown when Red=255 and what colour of white is meant when Red=255, Green = 255 and Blue =255. It also describes how the intermediate values move from 0 through to 255 – known as the tone response curve (or sometimes “gamma”).
Examples of colour spaces are (Adobe RGB1998, sRGB IEC61966-2.1)
With the information from the document profile, the colour management system knows what colour is actually represented by the pixel values in the document.

2.What colour will be displayed on the printer/monitor if it is sent certain pixel values?
This is the job of the monitor/printer & paper profile. It should describe exactly what colours the device is capable of showing and, how the device will respond when sent certain values.
So with a monitor profile that is built to represent the specific monitor (or a printer profile built to represent the specific printer, ink and paper combination) then the colour management system can predict exactly what colours will be shown if it sends specific pixel values to that device.

So armed with those two profiles, the colour management system will convert the numbers in the document to the numbers that must be sent to the device in order that the correct colours are displayed.

So what can go wrong :

1.The colours look different in Photoshop, which is colour managed, to the colours in a different application which is not colour managed.
This is not actually fault, but it is a commonly raised issue. It is the colour managed version which is correct – the none colour managed application is just sending the document RGB numbers to the output device regardless without any conversion regardless of what they represent in the document and the way they will be displayed on the output device.

2.The colour settings are changed in Photoshop without understanding what they are for.
This results in the wrong profiles being used and therefore the wrong conversions and the wrong colours.
If Photoshop is set to Preserve embedded profiles – it will use the colour profile within the document.

3.The profile for the output device is incorrect.
The profile should represent the behaviour of the device exactly. If the wrong profile is used it will not. Equally if the settings on the device are changed in comparison to those settings when the profile was made, then the profile can no longer describe the behaviour of the device. Two examples would be using a printer profile designed for one paper, with a different paper. A second example would be using a monitor profile but changing the colour/contrast etc settings on the monitor.
The monitor profile is set in the operating system (in Windows 10 that is under Settings>System>Display >Advanced) which leads to a potential further issue. Operating system updates can sometimes load a different monitor profile, or a broken profile, which no longer represents the actual monitor.

 

 

There is one more scenario that is mentioned in this thread which is "soft proofing". That means simulating what the output will look like if converted to another profile. So it is possible to simulate any colour changes that might apply when printed with a particular colour printer profile if you have that profile installed on your system - hence the advice to request a copy of teh printer profile from your printer for soft proofing.

 

Colour management is simple to use provided the document profile is correct, always save or export with an embedded profile, and the monitor/printer profile is correct. All the math is done in the background.

 

I hope that helps

 

Dave

3 replies

Stephen Marsh
Community Expert
Stephen MarshCommunity Expert
Community Expert
March 24, 2021

Is this a solution looking for a problem?

D Fosse
Community Expert
D FosseCommunity Expert
Community Expert
March 24, 2021

As I said, it depends. Severe gamut clipping usually looks pretty bad.

 

A generally dense and opaque look with no "air" is typical for out of gamut areas, and very unattractive. Squashed and flat textures don't look good either. That's when a little effort can improve the result considerably, and if it's an important image, it's definitely worth it.

 

Slight gamut clipping is usually not a problem, and no solution required. The profile can handle it. Not seeing the original I don't know which one we have here.

 

This is why soft proof is the way to go and the gamut warning useless.

    Stephen Marsh
    Community Expert
    Stephen MarshCommunity Expert
    Community Expert
    March 24, 2021

    Exactly, my reply was to teenas96182878 as it is worth checking what a preview or actual conversion using different rendering intents and options looks like, before performing a whole lot a gyrations to fix something indicated by the gamut warning that may not be an issue in the first place.

     

    The image posted is in sRGB, but who knows what the CMYK destination condition or profile is?

     

    It's going to be printed at some PoD provider, perhaps leaving it in RGB may offer better gamut if they have their colour workflow setup sensibly (probably doubtful, but one can hope), or perhaps the PoD plce only accepts CMYK (which CMYK???)...

      D Fosse
      Community Expert
      D FosseCommunity Expert
      Community Expert
      March 23, 2021

      Hue/sat is fine, although personally I prefer Selective Color. It's more subtle, but also much less disruptive to the pixel structure and general image integrity.

       

      If I have more time on my hands, I dig a little deeper to find out exactly which channel is clipping and where (high or low end). In this case, it's most likely the red channel clipping at the low end.

       

      You can use "Blend If" to target any corrective adjustment pretty precisely to the clipped areas. Pick the red channel slider, and set it to affect the low values only. Split the slider and experiment with the range. Lower the opacity of the adjustment layer until it just brings it into gamut.

       

      It really varies from situation to situation. If the soft proof is acceptable, just ship it and be done.

        davescm
        Community Expert
        davescmCommunity Expert
        Community Expert
        March 23, 2021

        Have you tried just using proof colours to preview the image in the printer/paper profile and seeing what it looks like with relative vs perceptual rendering intent. The trouble with the gamut warning is that it does not let you know whether the colour is just out of gamut and will be altered very slightly on printing or way out of gamut and will be altered significantly. So you might be using a sledgehammer to crack a walnut.

         

        If the colour is way out then I would use a hue sat layer / but target that specific colour range and  minimise the adjustment to bring it close and let the ICC colour management process do the rest.

         

        Dave

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