A question of colour?

[manoz]

I didn't know where to put this but here goes. I've been working on a photgraphy gallery(as I've posted before) for a uni project. I spent quite a while modelling and rendering with CAD and I was very happy with it and how it looked on the screen. When I came to print it, I wasn't so happy. (I use the departments printing service since I need the sheet at an A1 size). The problem was that the picture appeared darker and some of my whites appeared yellow. Has anyone got any tips to improve this? I haven't the first clue about colour reproduction. I know I can't get it exact but I was hoping for something closer. Is there anything that I need to do in photoshop? Do I find out what type of printers they use? etc.. Any clues would be appreciated

 

[ichabod crane]

if you check the printer manufacturers site they should have a color chart, which shows the most common colors that can be produced from the printer, quite a big color chart. but you need your colors to be as close to that as possible,

other than that simplist way is to get a smaller printer from the same manufacturer i.e i use a HP plotter and an HP A3 printer both use same ink an pens so i print test pages in A3 altering colors till i get them right on A3 then plot. to me this is the easiest and best way to do it. best method i have found

Or use pantone colors in photoshop i know most HP plotter/printers can produce all pantone colors

 

[ChroniC]

snip

Correct me if im wrong but surely if his monitor is not calibrated correctly to match a sRGB, or adobe1998 i.c.c profile then he will always have problems printing, as the colour he sees will never be a true match.

I would set your monitor temperature to 6500k (sRGB), then apply this colour profile on your colour management settings of your gfx card.
http://www.adobe.com/digitalimag/adobergb.html

assuming as i am that most if not all printing manufactorers print to this colour standard?

 

[ichabod crane]

most people dont bother to calibrate monitors, and if he is using university displays they will be setup as they are, so the trial and error method i mentioned above is best to get the right color out of the printer rather than on the screen.

 

[manoz]

snip

Cool, didn't think to look on maufacturers website, I'll check what printers the department has and see the colour chart but I can't afford an A3 at the mo even though I want one badly, thankfully it isn't that expensive to print off in the depart so I can test different colours and paper types. I'll have to check out the pantones aswell.

snip

I had a suspicion of monitor(I have a samsung SM-215TW) profiles aswell but I thought since my images are generated by me and not photos then as long as I'm happy with what I see on the screen, I'd be happy if the colours printed near enough correctly but it's a misconception I guess

most people dont bother to calibrate monitors, and if he is using university displays they will be setup as they are, so the trial and error method i mentioned above is best to get the right color out of the printer rather than on the screen.

Yeah. kinda sucks cos I have to use the uni computers to photoshop my work but most of the time I don't need to touch my renders after I've done them on my computer

 

[ChroniC]

I had a suspicion of monitor(I have a samsung SM-215TW) profiles aswell but I thought since my images are generated by me and not photos then as long as I'm happy with what I see on the screen, I'd be happy if the colours printed near enough correctly but it's a misconception I guess

But the thing is, if your monitor isnt calibrated to the specific colour temperature, for example you are working on rgb 6500 in photoshop but your monitor is displaying 6200k, you would see bright white but it would print at 6500k and be slightly yellow.

Mind this is only true if the printer is calbirated to the same as the monitor, which is the point ichabod crane is trying to make, and its a valid one. The problem there is unless you know what colour profile they are printing with you cannot match your monitor to there printers, unless like he says you do a trial and error test page.
So yes you do need to find out what calibration they are use and adjust your monitor accordingly.
Some places with give you a colour card, or ask the university or printing place what profile they are using.

 

[manoz]

^Ok, that's the best route I should take then, thanks for all the help

 

[Irish_Tom]

Mate apart from the monitor not being calibrated your biggest problem is that you are working in rgb and your printer is printing cymk. rgb (screen based stuff) has a wider range of colours that it can replicate.
4-colour printing or cmyk (cyan magenta yellow and key=black) is the system most printers use. There is no way to print rgb so you are going to have to change your work in photoshop to cmyk. There's just no other option for getting accurate colour matches from screen to paper.

Or use pantone colors in photoshop i know most HP plotter/printers can produce all pantone colors

This would work only if the printer had the specific pantone inks. The whole point of Pantone is that it's a system of specific inks which match to a code. they are pre-mixed inks, unlike cmyk which prints degrees of each colour over the top of each other to achieve the full range of colours. You can't print Pantone colours using cmyk, the printer will simply guess to the closest cmyk value of that pantone colour if it doesn't have the ink available.
Pantones are usually used for block colours or logos with one or two colours in them because they are exactly the same every time they are replicated (Cadbury's chocolate purple for example is always the same because it's a pantone value). No one in their right mind would print photo's using pantones because your printer would pretty much have to use the entire range of inks to replicate the huge amount of colours found in a photograph. It's just not feasable.

There seems to be quite a bit of misinformation in this thread. The only way you are going to get exact matches from what you see on screen to what gets printed is have both monitor and printer calibrated and to convert your work on screen to cmyk.

Panzer

 

[ChroniC]

Mate apart from the monitor not being calibrated your biggest problem is that you are working in rgb and your printer is printing cymk. rgb (screen based stuff) has a wider range of colours that it can replicate.
4-colour printing or cmyk (cyan magenta yellow and key=black) is the system most printers use. There is no way to print rgb so you are going to have to change your work in photoshop to cmyk. There's just no other option for getting accurate colour matches from screen to paper.



This would work only if the printer had the specific pantone inks. The whole point of Pantone is that it's a system of specific inks which match to a code. they are pre-mixed inks, unlike cmyk which prints degrees of each colour over the top of each other to achieve the full range of colours. You can't print Pantone colours using cmyk, the printer will simply guess to the closest cmyk value of that pantone colour if it doesn't have the ink available.
Pantones are usually used for block colours or logos with one or two colours in them because they are exactly the same every time they are replicated (Cadbury's chocolate purple for example is always the same because it's a pantone value). No one in their right mind would print photo's using pantones because your printer would pretty much have to use the entire range of inks to replicate the huge amount of colours found in a photograph. It's just not feasable.

There seems to be quite a bit of misinformation in this thread. The only way you are going to get exact matches from what you see on screen to what gets printed is have both monitor and printer calibrated and to convert your work on screen to cmyk.

Panzer

That would be the case for a standard printer, but if you take it into a printing service they should be able to replicate rgb. The printers i use ad university have and 12 cartridges, not 4.
But i suppose what you say cant hurt.

 

[Irish_Tom]

That's true, some printers have more than 4 inks, my R200 at home has 6, but they are just various grades of the same four colours, light cyan, cyan and dark cyan etc. While this does increase the colour range it's still not going to be RGB.

The fact that RGB uses light to make it's colours and CMYK uses dye should be enough to show that they are never going to be exact. Here's an image of the visible colour range, and the colour ranges of RGB, CYMK and Pantone.

It's clear that in certain places it just doesn't match up. When you send a document to print the RGB values get converted to CMYK at some point in the journey. You are much better off making that point right at the start before you've even sent it to print, where you have full control because once it's converted you can adjust it accordingly.

Panzer

 

[growse]

The RGB/CMYK debate aside, I think it's possibly important to mention that you don't calibrate your monitor to a particular profile, like sRGB or AdobeRGB. Equally, you don't calibrate your monitor to your printer. A monitor is either calibrated, or it isn't. Ditto the printer. A calibrated device is one which has an accurate colour profile to translate image colours into actual colours displayed on the device.

So if you have a calibrated profile for your monitor, and a calibrated profile for your printer, any colour managed app should be able to produce as similar as is possible colours on your screen to your printer, as long as it falls within the gamut of the colourspace being used.

If an area of an image says "Red", the app should look up what colour that's meant to be for you on your monitor in the monitor profile. When you print it, it looks up whatever colour matches "Red" in the printer profile and prints that. If you have two completely different calibrated monitors, it is likely that the application will send different colour information to each for the same image, because they display colours differently. This is to get the image looking exactly the same on each monitor.

The colourspace that an image is in (sRGB, for example) merely says what range of colours are present in that image. AdobeRGB has a slightly different gamut to sRGB, and therefore can show slightly different colours. These still need to be translated acording to the profile of the device that you're viewing it on - a different colourspace just means that some colours might be more accurate on certain devices. AdobeRGB produces more accurate colours for CMYK printing as it's gamut is closer to CMYK iirc. The only way to be sure is to convert the image to a CMYK colourspace. This, again, still needs to be translated via your monitor profile for display, and it's feasable that some of the colours might not fall within the mointor's display gamut, so will be an approximation. It's not usually that much of a problem though.

Correct me if im wrong but surely if his monitor is not calibrated correctly to match a sRGB, or adobe1998 i.c.c profile then he will always have problems printing, as the colour he sees will never be a true match.

I would set your monitor temperature to 6500k (sRGB), then apply this colour profile on your colour management settings of your gfx card.
http://www.adobe.com/digitalimag/adobergb.html

assuming as i am that most if not all printing manufactorers print to this colour standard?

This is bad advice, because setting your monitor profile to adobergb assumes that the monitor is a perfect adobergb device, which most definitely won't be true. You need to get the correct profile for your monitor from the manufacturer's website, as all monitors are different. If you have the cash, get a calibrator and create your own, which will probably be more accurate than the manufacturer's.

 

[manoz]

The printers at uni use 4 inks (CMYK). Found out today that they have three different plotters and they spread the work over them randomly and according to what paper is needed. Was looking at someone elses work who had a lot of sheets but had a consistant border and they were all different shades!! I'm gona have to test all of them and they suggested I request what printer I wana use everytime I submit.

snip

They suggested that too, didn't occur to me that I'd have to switch. I'd open an image and it opens in RGB automatically. One thing I'm not sure about is the colour depth, would it be better if I save as 16 bit or 8 bit? My renders are saved as 16bit(well actually 48bit PNGs) but appear as 16bit in photoshop.

snip

My monitor comes with some kinda of "Natural Colour" calibration software which I haven't tried. I can't afford a calibrater and I'm not that fussed about getting it spot on, just that there was a noticable differnce, I don't mind if there is a bit of difference. Is it best if I use my own Monitor calibrator(Natural Clour) then?

 

[Irish_Tom]

I'd open an image and it opens in RGB automatically

It's best to work on your images in RGB because of the extended colour range, then convert and tweak just before printing. I would save a second copy of the file in cmyk.

As for the colour depth, I always save my RAW's as 8bit Tiffs but that doesn't necessarily mean its right, would quite like to know the answer to this too.

You can get a basic calibrator for £50 but the better ones are obviously more, if you get a profile from the manufactures website and then (assuming your using windows) right click on the desktop, go to properties and then advanced, go to colour management and load up the profile you just downloaded.

Growse your quite right, thanks for the correction, I'm getting my terminology wrong!

Panzer

Panzer

 

[ChroniC]

This is bad advice, because setting your monitor profile to adobergb assumes that the monitor is a perfect adobergb device, which most definitely won't be true. You need to get the correct profile for your monitor from the manufacturer's website, as all monitors are different. If you have the cash, get a calibrator and create your own, which will probably be more accurate than the manufacturer's.

I was informed by my tutor that the either sRGB or adobe1998 profile is as close as you can get to true RGB, and that any monitor is capable for a temperature setting of 6500k which is corrospondant to sRGB's white point. So basically if you dont have a calibration tool then this is a simple alternative. Ive yet to find a profile from AOC, and my prints have looked almost identical on my monitor and the macs in the studio, with little or no problems printing, so as to say if you dont want to spend much and want a close representation it isnt bad advice just an alternative.

I think this explains it better
http://www.normankoren.com/makingfineprints1A.html

 

[growse]

I was informed by my tutor that the either sRGB or adobe1998 profile is as close as you can get to true RGB, and that any monitor is capable for a temperature setting of 6500k which is corrospondant to sRGB's white point. So basically if you dont have a calibration tool then this is a simple alternative. Ive yet to find a profile from AOC, and my prints have looked almost identical on my monitor and the macs in the studio, with little or no problems printing, so as to say if you dont want to spend much and want a close representation it isnt bad advice just an alternative.

I think this explains it better
http://www.normankoren.com/makingfineprints1A.html

I'm not disputing that sRGB and AdobeRGB are good colour spaces, sRGB is the default profile applied is most OSs. My issue is that applying the sRGB default profile across a bunch of different monitors will produce vastly different results across those monitors, because every one is different and no monitor's gamut exactly matches that of sRGB. You might get lucky and only work with images that don't show the differences very much, or the differences might not be that great, but you by no means can rely on your monitor giving you accurate colours on the sRGB default profile. I would say that applying the AdobeRGB profile is bad advice because to my knowledge, most monitors try to behave like sRGB. The best and easiest thing to do is to get the profile off the manufacturer. I've yet to come across a monitor where I can't do this.

I use my IBM laptop with an IBM TFT at work, and when I get home to use just the laptop screen, I have to load a different colour profile because using my laptop monitor with the profile created on the tft at work makes the colours look completely wrong. It's not all about colour temperature, there's a lot more to it than that.

AOC do provide profiles for their panels, they're over at http://www.nam.aocdisplay.com/support_drivers_popup.html

 

[ChroniC]

I would say that applying the AdobeRGB profile is bad advice because to my knowledge, most monitors try to behave like sRGB. The best and easiest thing to do is to get the profile off the manufacturer. I've yet to come across a monitor where I can't do this.
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Im not argueing its futile, and i dont see the point. Adobe1998 and srgb are so similar its probably unnoticable.
An seeing as they both apply a perfect white point representation at 6500k, if your using a several different crt's all at that setting you shouldnt have a major difference.
I dont understand what you mean by its not all about colour temperature. Of course it is.
If your monitor is producing a perfect 6500k temperature, and its is applied with an sRGB profile which as i said has a white point of 6500k then your gfx card should be producing perfect white? I have several screens here, and applied in that way they all look exactly the same.
If the gamut of certain monitors are different, because of a poor monitors ability to produce a wider range of colour, like you say some might be different slightly, but in the way i have calibrated mine i will always have the same perfect whiite and most if not all colours the same.

Thanks for the aoc site though, i applied theres, and it made zero difference also.

 

[growse]

Im not argueing its futile, and i dont see the point. Adobe1998 and srgb are so similar its probably unnoticable.
An seeing as they both apply a perfect white point representation at 6500k, if your using a several different crt's all at that setting you shouldnt have a major difference.
I dont understand what you mean by its not all about colour temperature. Of course it is.
If your monitor is producing a perfect 6500k temperature, and its is applied with an sRGB profile which as i said has a white point of 6500k then your gfx card should be producing perfect white? I have several screens here, and applied in that way they all look exactly the same.
If the gamut of certain monitors are different, because of a poor monitors ability to produce a wider range of colour, like you say some might be different slightly, but in the way i have calibrated mine i will always have the same perfect whiite and most if not all colours the same.

Thanks for the aoc site though, i applied theres, and it made zero difference also.

It's not all about white! There are other colours too!

Monitor A could have a gamut that's heavily biased toward green. Monitor B could have a bias towards blue. Both display the same white at 6500K. Both of these monitors need different profiles to display images as accurately as they can. Of course, if they can't display a particular colour in the sRGB colour space, there has to be an approximation, and that's what the profile will do. It's not about the gamut being "wider" or "narrower", it's about the colourspace being different.

Like I said, you might be lucky in posessing a monitor that has a colourspace that is very very similar to sRGB so that needed corrections are minimal. Or, you're just using images whose colour range doesn't expose any differences between your monitor colourspace and sRGB. It's certainly not true of all monitors - my Samsung 244T is slightly blue-biased, and there is a significantly noticable difference between having the calibrated profile applied and the default sRGB profile applied. The Samsung profile is somewhere in between these two. Better than sRGB, but not perfect. It's not about how 'poor quality' the monitor is. All monitors are different and all have different colourspaces. Doesn't make them bad, makes them in need of calibration.

 

[ChroniC]

Ok yes, but seeing as adobe1998 and srgb both use the same white point, and adobe has a colourspace larger than srgb and larger than most monitor gamuts, then at 6500k you would have a perfect set point of white and the ability to reach almost all colours, even if your monitor is biased towards a certain colourspace. simple calibration.

I wont however deny that a manufactorers profile will be better, but i have had trouble finding them in the past and find 1998 to work just as well.