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Monitor Colour inconsistencies

Discussion in 'Printing & Print Design Forum:' started by Studio_SG, Jan 23, 2014.

  1. Studio_SG

    Studio_SG New Member

    Hi guys,

    I have designed a logo for a client which displays much differently on her monitor than how i designed it. The design should show more as a grey but is showing as a purple on her machine. I wasn't too worried at first as I thought it most likely be a calibration issue on her machine. However she since tested it on her other machine and had same issue which worried me slightly.

    It looks how it should on both my iMac and macbook but on her both windows machine it shows more bluey - purple. I have since tested on other windows machines and get a more bluey purple colour. The macs I've tested so far display the 'correct' colour i designed it and mostly all other windows machines displayed it more as a bluey purple. My girlfriends iPad did display more blue too!??

    The CMYK values I have chosen are as follows C47 M40 Y24 K1. Looking at the significant Cyan and Magenta values, is this the reason the other monitors are interpreting these colours more? If so how can I achieve the colour displayed on my monitor to look correct on other monitors? I'm guessing at a lot of stuff at the mo! Can anyone shed any light on this? I get that monitors will display differently and there may be calibration issues here and there but I would have thought these differences would be subtle.

    Any help/advice would be greatly appreciated


  2. hankscorpio

    hankscorpio Moderator Staff Member

    Monitors display in RGB not CMYK.

    For screen logos it should be in RGB, Adobe RGB is the most reliable.

    For the web sRGB is more desirable.

    And for print it needs to be CMYK.

    Realistically - I'd have designed it using LAB values from a Pantone book.

    LAB values convert to destination profiles, like Adobe RGB, sRGB or CMYK much more uniformly.

    This ensures consistency across a variety of mediums.

    I recommend you take a look at Colour Management with - you can get a free trial.
    Studio_SG likes this.
  3. Studio_SG

    Studio_SG New Member

    Hi Hankscorpio,

    Thank you for your reply.

    Apologies, I should have explained my self a little clearer. I understand that designing for print should be in CMYK and for web RGB. The logo needs to be used for both print and web so I designed in CMYK and exported for web using RGB. The files I exported included Screen based (jpeg and png) and print (Tif, EPS and PDF)

    I believe the PDF file did look correct on my clients computer but all others including for print and screen had the purple colour.

    Is there any tutorials you could point me to regarding Pantone LAB values? Is this the most consistent way to keep colours looking correct through all monitors?

    Thanks again for you response on this

  4. hankscorpio

    hankscorpio Moderator Staff Member

    CMYK has a much narrower gamut than RGB.

    Ideally - you would start with Pantone then use the LAB values to convert to CMYK and RGB for various uses.

    Using Spot colours with Pantone (or other colour matching system) and using LAB conversion when converting to CMYK or RGB is the surest way to get colour consistency.

    You have to understand colour comes in different Gamuts (a limited range of colours displayable).

    CMYK and RGB are different gamuts.

    RGB has a wider gamut than CMYK.

    Thusly, CMYK has a narrower range in gamut.

    CMYK can never ever ever replicate correctly in RGB - it simply won't happen.

    Wheras, if your logo is in RGB then converting it to CMYK is easier as RGB has a wider gamut so your colours are more closely matched.

    That's why starting with a Pantone book and selecting the colour from there for the logos will give a better gamut output for various devices.

    Again, Pantone is a limited range of colours (gamut) that cannot be reproduced with CMYK or RGB.

    But Pantone values give a CMYK build and a RGB build along with their swatches.

    And when you convert spots (pantones) to CMYK or RGB you can choose to use the LAB values for the conversion.

    This gives the best approximation for the conversion to CMYK or RGb depending on your output intent.

    Different output intents have different builds of CMYK or RGB.

    For example, a coated and uncoated paper would require different CMYK values, or a printer in the US would use Swop Coated and Europe would use Coated Gracol or Coated Fogra 39 etc.

    If you have just CMYK in the values then those same values are used in the CMYK output intent across all the media.

    In reality the conversion to CMYK should be done for the output intent - and using LAB values is the best way to convert for different stocks of paper, or different printing conditions.

    Similarly - converting plain CMYK to RGB is a crapshoot - because CMYK doesn't have the necessary gamut (range of colours) to replicate a RGB gamut. So you lose some colour consistency.

    Basically your CMYK will always be out of gamut with RGB - all the time.

    Again - the colour management tuotorials on with a free trial are a great help in understanding this.
    Studio_SG and Stationery Direct like this.
  5. hankscorpio

    hankscorpio Moderator Staff Member

    Plus you may have done some colour calibration on your monitor, whereas someone else may not have. Or using an inappropriate colour profile all along.

    Viewing colours on screen to judge colour is a crapshoot too unless you have a colour calibrated monitor.

    And someone who has never colour calibrated their monitor is going to have difficulties in viewing the resulting colours.

    The PDF probably look correct because PDFs are a "wrapper" for the content within it. It may have held some colour output intent values within the file that allowed it to display correctly in Acrobat.

    But files converted from CMYK to RGB for the web can't ever replicate properly.
    Studio_SG and Stationery Direct like this.
  6. Studio_SG

    Studio_SG New Member

    Hey, really appreciate your time to explain this to me. So it seems the best way of choosing colours is to start with a pantone and work from there. I have a lot to learn and get my head around! I am a member of Lynda so I will look up colour management tuts on there.

    Thanks again for your help with this

  7. Studio_SG

    Studio_SG New Member

    Just wondering, as regards to your suggestion - 'Ideally - you would start with Pantone then use the LAB values to convert to CMYK and RGB for various uses.'
    Are you able to point me to any tutorials on how this is done?

    Thanks in advance

  8. hankscorpio

    hankscorpio Moderator Staff Member

    Well in Illustrator you can go the swatches flyout menu and choose Spot Colour Options

    And choose the LAB values from the Book manufacturer.

    In InDesign you can choose the Ink Manager from the Swatches Flyout Menu and choose Convert all Spots to CMYK - Use Lab values.

    Not 100% sure about Photoshop - I don't do a lot of spot colouring in there.


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  9. Studio_SG

    Studio_SG New Member

    Thanks for this

  10. @GCarlD

    @GCarlD Well-Known Member


    I am fairly new to Lab myself, partly due to the fact that I have never needed to use Lab for obvious reasons. I understand it works by using Lightness, Tint and Temperature giving it a much broader spectrum, as opposed to the limited CMYK or RGB that we are all very familiar with. I do wonder though, what are the cons of using Lab? Is it that it imposes such a vast range of colours that they would be undetectable by certain monitors/devices? So in a sense you need to be careful what colours you are working with in Lab? Or am I completely wrong?
  11. hankscorpio

    hankscorpio Moderator Staff Member

    LAB acts as a translation and is core to colour management.

    There could be issues with how black separates, say for text, you don't want that in CMYK you just want that on the K channel.

    But it's all in how you have your colour management system setup to handle things like that.

    Frankly, I'd put it on 100%K, and then use the LAB values for the colour elements.

    This would ensure the 100%K in tact when making the CMYK file.

    But the LAB values could be translated into whatever colour profile output intent you choose for CMYK.

    It's a lot to get into here - but you should really check out some Colour Management theory if you get a chance.

    This book is one of the finest on the market Real World Color Management (2nd Edition): Bruce Fraser, Chris Murphy, Fred Bunting: 9780321267221: Books
  12. Studio_SG

    Studio_SG New Member

    Sorry, I have another question! Once you have checked the relevant LAB values option as in your illustrator example is that all that needs to be done? Is there then a particular process for saving my file for web use - RGB? Sorry if it seems a dumb question I just want to get it right. Do i just export for web?

  13. hankscorpio

    hankscorpio Moderator Staff Member

    Basically that's it.

    You can test this by selecting different RGB profiles, and selecting the spot colour use CMYK values instead of Book.

    See what differences you can notice.
    Studio_SG likes this.
  14. I hope you won't mind if i clarify a few things as I think a few of the points are a little unclear.

    "CMYK and RGB are different gamuts." - No. CMYK are colourants. When you work in Adobe CS you work in a specific CMYK colour space (default is US Web Coated SWOP, but FOGRA39 is more common now). Those colour spaces represent different things. US Web Coated SWOP represents all of the colours that can be reproduced using SWOP certified inks on a litho press, on a particular stock, with a certain dot gain, with etc etc... The "Gamut" of US Web COated SWOP means the range of colours in that particular colour space - the range of colours that a press can produce with those inks on that media.

    The same applies to RGB. RGB are illuminants. Standard working space in Adobe is sRGB - an imaginary colour space designed to represent the average colour capabilities of an internet viewing monitor. AdobeRGB is just a different RGB colour space using different illuminants... NikonRGB represents all of the colours registered by the sensor on a Nikon etc etc the same theory applies as with CMYK above.

    When you're designing, it doesn't matter which you work in, provided you understand what these things stand for. Define a colour as four percentages or three percentages, makes no difference at all. But you must know "PERCENTAGES OF WHAT" If you answer that "percentages of CMYK" then the next question is "WHICH CMYK?" Imagine asking a paint store to mix 20% blue paint with 30% yellow paint. Then going into another paint store, doing the same thing. Unless you specify which specific brand and shade of blue and yellow you're meaning, you'll get the right mix, but completely different colours. It's all numbers, and if you don't understand what those numbers represent, or what is happening when you convert from one definition to another, you'll lose control of your colour.

    "RGB has a wider gamut than CMYK. Thusly, CMYK has a narrower range in gamut." True most of the time in standard colour spaces, but not necessarily so. It's just numbers. There are small RGB spaces and large CMYK spaces.
    Try this article about colour spaces Colour Spaces | Hudson

    "CMYK can never ever ever replicate correctly in RGB - it simply won't happen." - I've got several softproofing monitors here that show me exactly what's about to come out of my printer that prove that wrong.

    "Wheras, if your logo is in RGB then converting it to CMYK is easier as RGB has a wider gamut so your colours are more closely matched." Some confusion here I think. I think you mean the reverse. What I think you mean is - if you design in a small colour space then if you convert to a bigger space all of your colours can remain the same, whereas if you design in a large space and then need to convert to a smaller space you'll end up changing your colour.

    "Pantone is a limited range of colours (gamut) that cannot be reproduced with CMYK or RGB." Now you've lost me. Pantone is an extensive range of colours, nearly all of which can be produced by an AdobeRGB capable monitor, and 97% of which I can print on some media on some printers.

    "Different output intents have different builds of CMYK or RGB." Please see my comment above re: colour spaces. You're using "builds" to mean colour spaces.
    The first image in this article shows the same CMYK percentages in different colour spaces - effectively demonstrating what you're meaning. In different colour spaces, the same numbers give different colours - RGB or CMYK? Colour Spaces - what should you work in? | Hudson

    "converting plain CMYK to RGB is a crapshoot" Interestingly, there's no such thing as "plain CMYK". In Adobe CS, even if your document is showing as "untagged CMYK" you're working in your CMYK Working Space. If you're defining a colour as percentages, to see anything, you have to know percentages of what.

    "because CMYK doesn't have the necessary gamut (range of colours) to replicate a RGB gamut." A lot of the time if you design in a large colour space like AdobeRGB and are printing on a SWOP press - what you're describing happens to be what you'll see. But this isn't an RGB vs CMYK spaces thing. For example, the gamut of my JV3 printing on a particular vinyl, exceeds the gamut of sRGB in most areas. Converting between sRGB and my CMYK profile for that product would lead to almost no loss of colour.

    "Basically your CMYK will always be out of gamut with RGB - all the time." No, that's simply not true. If your design is in a large colour space and you convert to a smaller colour space some colours may be "out of gamut" ie. exist in the large space and don't exist in the small space. But a lot of the colours will exist in both gamuts, and converting those should lead to no change in colour. This article has some images in it you'll be interested in. It shows that the gamut of my JV3 printing on LD3811G vinyl can achieve colours outside of the gamut of AdobeRGB. RGB or CMYK? The CMYK habit discussed! | Hudson

    I'm sorry that I've picked at one of your posts here hankscorpio, it is not my intention to offend. I think some of what you were meaning was lost in what was written, and I hope I've helped rather than annoyed.

    If designers understand what colour spaces are, knowing that they are using them like it or not, then they pay more attention to converting accurately between spaces. Adobe CS has gamut warnings and proofing options built in. You can see what will happen to your colours when you output or convert into different spaces... It's just numbers, and none of it is that complicated once you know what the terms really mean.

    Your book recommendation was spot on. Fraser's work is the bible on this subject! Worth taking a look at the IDEAlliance Colour Management Professional Qualifications too if this is something you use on a daily basis.
    hankscorpio likes this.
  15. Scott, going back to your original post... Your issue isn't about colour spaces. If your monitor is displaying the cmyk make up you mention as a neutral then your monitor is a long way out. In any colour space those values will give you a purple. Get yourself a basic colourimeter or spectrophotometer and software and profile your screen. You can't work in colour if you can't view colour sensibly.

  16. Here's a link to an old article summarising working spaces which may help folk understand the "which cmyk" or "which rgb" question. Regards.

    Specifying working spaces
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  17. hankscorpio

    hankscorpio Moderator Staff Member

    Thanks for clearing up the points. I see where in my posts I may have been a bit misleading - trying to summarise into a few paragraphs wasn't easy :icon_smile:

    Well - yes there are exceptions to colour management in every workflow, well not exceptions, but different rules. And I wasn't thinking on the lines of vinyl or large format printing.

    I was trying to summarise how colour can be affected by changing from RGB to CMYK or vice versa and how the different output intents can cause colour shifts.

    Where if they worked in CIELAB they'd have a better conversion going from medium to medium.

    But thanks again for clearing up the bits I wasn't very clear on.

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