Newbie to Photoshop/Digi photos- problem

[eliseboymac1]

Hi chaps, a little help to understand a problem I have with Photoshop CS2 would be very much appreciated.

Started to play around with the colour balancing / saturation / shadows etc with some of my digi photos.

Photo1
Started with a jpeg file, converted to CMYK, altered the colours etc, and then saved as a tiff. Open with standard windows image tool or in the explorer thumbnail preview (and in PhotoSuite 8 at work) and all looks fine

Photo2
As above, but also needed to do some fixing (remove a dustbin?) by using the cloning tool etc with the surrounding pixels. Saved as the default psd file. The print shop only works with jpegs or tiffs. Resaved as tiff (no compression). When opened in the above programs, the colours are 'inverted' and are distorted sometimes. When I open again in CS2, the photo looks correct?

What's happening and how do I fix it?

Fortunely I still have the original jpegs and psd files to work with.

Much obliged.

[robbieduncan]

Re: 2. Did you save it as an 8bpp or 16bpp TIFF? Some programs may struggle with 16bpp.

[eliseboymac1]

Thanks for the response.

It was 16bpp. If I drop it down to 8bpp, will the image quality be ok? How much does 16 or 8bpp effect the colour?

Thanks again

[stuart b]

Your JPEG starting point is 8 bit, so I'm not sure why you would covert to 16 bit TIFF. I suppose it's possible that if you then do a lot of manipulations in PS that you'll get less degradation (16 bit is regarded as an essential start point should you need to do manipulation in Lab Color mode for example for this reason).

I assume your camera does not have a RAW mode or else you would be using it?

In practice, if you're starting with JPEGs, you should be fine to do moderate amounts of PS work before sending as a high quality JPEG for printing. The one thing to avoid is any unnecessary saving/re-opening in JPEG. So whilst a photo is work in progress you could use TIFF as you are or Photoshop's own format.

I've not seen anyone use CMYK for photo prost processing either. It's more suitable if you need to produce colour separations for pro printing as I understand it.

I stand to be corrected - these are just the illusions under which I labour.

Stuart

[VxDuncan]

For a start I wouldn't bother changing to CMYK. THe CMYK Gamut (range of colours) is different to RGB and is probably the cause of your strange colour issues. THe fact that they are happy to recieve JPEGS or TIFFs means they want RGB files (the colour space the vast majority of people will submit files in). Best to let them convert between colour spaces with there own software - after all they may be using more than just the CMYK inks.

You should however work in Raw in the camera, and process in 16 bit colour - converting to 8bit at the end if you need to. Make sure your monitor is calibrated as far as possible (adobes monitor calibration is better than nothing) and use a CRT rather than cheap LCD. Submit in 16bit tiff if you need to, but if you maintain the information properly when processing high quality JPEG work make much difference, other than make the printer your friend by not crashing the print server.

[eliseboymac1]

Thanks for the response Stuart and Duncan.

The camera which I've had a little while now does support RAW (one of the reasons why I chose it), but I've yet to use it since I didn't have a PC or PS until recently. I'm going through some of my old photos to learn the basics. Also I didn't have a large enough memory card for RAW to be practical. I'll have a go with RAW from now on.

I spoke to the print shop just and they reckon that its not uncommon that some files saved in CMYK go inverted in apps other that PS. They actualy recommended using the normal Adobe RGB mode as they use a film scanner(?) to print the photo. I read yesterday about the jpeg re-save issue as well. Thanks.

Edited by eliseboymac1 on Friday 12th January 22:26

[andybuk99]

Dont touch cmyk unless you have a full understanding of icc profiles and are familiar with the output printers profile. You certainly wouldnt make any colour correction work in cmyk as it is a smaller gamut than rgb. You will not gain anything from upsaving a 8bit into 16bit mode.

[stuart b]

I've settled on shooting RAW for slightly more serious stuff (to be honest this is often because I need to correct a lot of things I should have got right in the camera), but still use JPEG for events, family and general walkaround. Processing RAW can turn into a serious time-burner in my experience (especially if you are not using the manufacturer's software and don't get all the in-camera settings applied to the shots). Sometimes better to spend more time shooting pics and try to have them right coming out of the camera (one day!).

Colour spaces is another massive topic which I don't profess to understand. Suffice to add that some say that Adobe RGB gives a bigger range of colours whilst the truth is actually somewhat more complex and it does not necesarily give better results than the alternatives. If your printer is recommending Adobe RGB then it sounds like a no brainer though. I understand that sRGB is usually a better choice for web use however. Personally I haven't got to the stage where I have had to worry about the difference.

Stuart