Colour reproduction of PC Monitor and Projected image.

[JEB]

Hi

I feel certain that this is a common issue and may well have been addressed before so please forgive me if this is so.

I am struggling to explain, in simple terms, to club members why our club laptop monitor and projector show different colours (when connected). I think I understand the reason but would like confirmation that my understanding makes sense!

Firstly images should be produced from the image editor (PS) etc. in sRGB, the monitor of the computer producing the image and that running PTE or displaying the image should also both be correctly calibrated as should the projector. Most projectors use sRGB.

My basic understanding of colour management is that any given colour has specific R, G, B, colour values and that calibrating equipment creates a profile that enables calibrated equipment to generate the correct colour values.

I also understand that a laptop or PC utilises a profile through its graphics card when generating an image.

When a PC is connected to a projector it uses the profile for the projector in order that the correct colours are projected. However as most PC's have only one graphics card they can only use one profile at a time so therefor use the projector profile to run the monitor while the projector is connected. Hence the wrong colours being produced on the monitor at that time. Am I basically correct?

I understand that MAC's are different and don't have this problem. I have to admit that as a MBP owner I have not noticed the problem when I use it with a projector. I don't use it very frequently in this way and believe that it would not in fact concern me particularly.

I understand that there are PC's with two graphics cards and projectors that utilise RGB but those are way out of budget for our club!

The opinions of those who understand this issue would be appreciated. But please remember that I am not a technical person!!!!

Regards

John

[Ken Cox]

John, for starters

see

http://www.mplonsky.com/photo/

and see where the 2 systems are set re grey card settings

ken

[cjdnzl]

Hi

I feel certain that this is a common issue and may well have been addressed before so please forgive me if this is so.

I am struggling to explain, in simple terms, to club members why our club laptop monitor and projector show different colours (when connected). I think I understand the reason but would like confirmation that my understanding makes sense!

Firstly images should be produced from the image editor (PS) etc. in sRGB, the monitor of the computer producing the image and that running PTE or displaying the image should also both be correctly calibrated as should the projector. Most projectors use sRGB.

My basic understanding of colour management is that any given colour has specific R, G, B, colour values and that calibrating equipment creates a profile that enables calibrated equipment to generate the correct colour values.

I also understand that a laptop or PC utilises a profile through its graphics card when generating an image.

When a PC is connected to a projector it uses the profile for the projector in order that the correct colours are projected. However as most PC's have only one graphics card they can only use one profile at a time so therefor use the projector profile to run the monitor while the projector is connected. Hence the wrong colours being produced on the monitor at that time. Am I basically correct?

I understand that MAC's are different and don't have this problem. I have to admit that as a MBP owner I have not noticed the problem when I use it with a projector. I don't use it very frequently in this way and believe that it would not in fact concern me particularly.

I understand that there are PC's with two graphics cards and projectors that utilise RGB but those are way out of budget for our club!

The opinions of those who understand this issue would be appreciated. But please remember that I am not a technical person!!!!

Regards

John

Your understanding of the problem is very good despite being 'non-techy'. We had the same problem with our club, we bought a new DLP projector and had complaints about the colour. When questioned, the members complaining did not have their own monitors calibrated and so had no basis for complaining about the projector. However, The projector wasn't all that flash anyway, so I calibrated it (Colorvision Spyder) with the club's Dell laptop. Some of the members had the same problem of getting their heads around the fact that the lappy screen was wrong when the projector profile was chosen.

Another problem was with judges who viewed the images for their comments. Almost invariably they would look at the projected image and say it looks different to what they saw on their own machine, so comments on blown highlights or blocked shadows or odd colours weren't supported by the projected image. This is a problem the club has to deal with this year when we restart in February (summer holidays in NZ).

For a start, we exhort all members to use sRGB exclusively and will inform the judges that all images are in sRGB. If they view them in an aRGB or other color space that's their problem.

I understand that PTE does not manage colour, it expects images to be in sRGB, which is perfectly ok with me.

Have a look at http://johnwiddall.wordpress.com/technical-notes/test-cards/ for more information, and the use of test cards.

[davegee]

John,

What method do you use to present your images? We use PTE. and give a judge the PTE EXE. there is no point in giving the judge individual images. If the images in the show are1920 x 1080 max and the judge is viewing on a 1920x1080 monitor the judge is seeing the images at 100%. All members have been advised to use sRGB and this works. Maybe it is not "correct" but it works. I have often wondered if clubs need a "standard" jpg image which all members can download and compare on their own systems.

An sRGB image in a PTE show works for me on both my own system and on the club's HD projector (whEn viewed in a PTE EXE).

DG

[PGA]

I am not a club photographer but I second the comments given by Colin and Dave. My cameras are set to capture using sRGB, my digital projector is taking the feed from my laptop, which has all its software set to run in sRGB, as has my desktop PC. My workflow is sRGB throughout and I never feel that the projected colours are "wrong".

One simple "rule" that I was given, to ensure that images to be projected are in the correct colour space, is to save them as JPEGs using "Save for Web", ensuring that the "Embed colour profile" box remains unticked. Save for Web will automatically convert the colour space to sRGB.

regards,

Peter

P.S. Those "Save for Web" instructions are based upon Photoshop Elements 11

[JEB]

Hi,

Thank you all for your responses.

You have given me the confidence to "battle on".

Regards and thanks,

John

[davegee]

I am not a club photographer but I second the comments given by Colin and Dave. My cameras are set to capture using sRGB, my digital projector is taking the feed from my laptop, which has all its software set to run in sRGB, as has my desktop PC. My workflow is sRGB throughout and I never feel that the projected colours are "wrong".

One simple "rule" that I was given, to ensure that images to be projected are in the correct colour space, is to save them as JPEGs using "Save for Web", ensuring that the "Embed colour profile" box remains unticked. Save for Web will automatically convert the colour space to sRGB.

regards,

Peter

P.S. Those "Save for Web" instructions are based upon Photoshop Elements 11

In the full Adobe product, when using "Save for the Web" the sRGB option is a Tick Box - I'm not sure what the default is, but when I have used it in the past it has always been set to "ticked". I would recommend using "Save for the Web" because it allows you to adjust the quality setting to optimise the JPEG while viewing at 100%.

I couldn't see the sRGB tick box in the "Save for the Web" utility in my version 10 of elements - it is probably elsewhere?

DG