Feeling kinda blue
Thanks for your responses so far guys. To answer the questions I've had: I let the printer chose the colour. I decided to send it a CMYK file because I'm used to preparing files for offset printing. Apart from that my idea was that if there was any noticeable colour shift I could perhaps compensate for it before 'pressing the button'.
In this case I didn't notice any shift (viewed in Photoshop) when I did the RGB>CMYK conversion. It would obviously be easier for me to send the RGB file to the printer but I thought the fewer steps it had to do automatically, the better.
I used Corel Draw to send the print file to the Canon MP640 because print preview did not work properly in Photoshop. My main idea when sending the print file was to allow the print software and machine to do the minimum work (resizing, changing colour model etc.) possible. If printing from and RBG file would make a big difference I'd be delighted. I didn't consider that myself earlier today.-- hide signature --
Gravity will make you crazy until you get the hang of it.
I thnk you should try to to open the original file ( Hope you did not conver to CMYK and then save it over itself ) and save it as a sRGB. That's all you really need for printing to a press.
Print it letting the Canon handle color. Do not turn on your preview on the driver. Print it in high quality and choose the correct paper type.
Also, if your monitor is not hardware calibrated to a proper standard then whatever edits concerning color and density you performed may not really be true.
Most all monitors are dset too bright and too blue or too high a color temperature. So we are led to edit the file till it looks good on our monitor which is not correct to being with.
You get the idea.
I just took a jpg and converted it to CMYK and when I toggle back and forth by clickink Control Z and see the same effect you are expereincling. A lot of my tones are very bluish ro cyanish in the CMYK version. sRGB looks perfect.
Hope that sheds light on the problem.