Please help me with my GF's christmas present.

[iambanana]

I also posted this over in the photoshop forum, but there was no response, so I thought I'd post it here. And I guess this applies to any digital medium anyway, so..yeah. Plus I'm in a bit of a hurry to get this done and need all the help I can get.

So my girlfriend keeps telling me how she loves this one painting of mine (Which has a very distinct style) and how she would love to have a huge print of it on her wall. Thing is, that one painting she likes was only supposed to be a quick sketch and therefore I only saved it as a tiny JPG, discarding the .PDF file. So I thought I'd make a new one, in the same style.
So here are my questions (Beware, extreme noobiness ahead.):

I should set my colours to CMYK, right? Just making sure.

Is there an easy way to set the resolution so that I can print it out on anything from 30 cm x 50 cm to 40 cm x 60 cm? Haven't quite made up my mind yet, you see. And it would be great to able to change my mind and use a lower or slightly larger size if I find out that the one I'm working on is going to look awkward in such a big size. I know that 300 DPI is the ideal resolution for prints, but what exactly do I put into the 'New File' dialog in PS? And will this allow me to change my mind about the size later? English isn't my first language, so I hope my that question came across alright.

[Flake]

CMYK, yes. Or you can work in RGB then switch modes later.

Edit: I am wrong, stay RGB.

Is there an easy way to set the resolution so that I can print it out on anything from 30 cm x 50 cm to 40 cm x 60 cm? Haven't quite made up my mind yet, you see
Work at the largest possible size you think you'll ever want to print it at.
If you decide to go smaller shrinking images is very easy, enlarging, not so easy.

[Elwell]

What kind of print? If it's going to be done on an inkjet, keep it in RGB.

[karmiclychee]

The way I do it - the way I've been told works, anyways - is to draw/paint first in RGB, then switch to CMYK. I don't precisely remember why though... I'm not sure if I'm right about that though.

As per printing... your safest bet is to make your file 300 DPI and work in actual size. So if the largest size you're considering is 40 x 60 cm, go with that size. You can always scale down, but you never want to scale up because then you're leaving your computer to pretty much guess how to fill in the gaps.

Hell, to be even safer, work in even larger dimensions than 40 x 60 cm and scale down from there. Stay at 300 DPI because either (i don't remember which) the human eye can't really discern beyond that point or that's usual print resolution. You'd just be adding to file size and making working with your document unruly.

Start your document at the resolution you want (300 DPI) and keep it there, you can always scale your dimensions down later.

[iambanana]

Alrighty then, thanks for the quick responses. Dunno if I'm printing on an inkjet. I plan on taking it to a photo store and print it on this thick (Around 1 cm) plastic/cardboard/woodish white board. Then I'll cover it in plexiglass. Do professional print shops usually have inkjets?

I have previously tried to work in RGB and then switch to CMYK, but I've noticed that the colours get a bit different. So I guess it's best to stay clear of switching modes?

[karmiclychee]

Probably, come to think of it. I have no idea why I thought that was a good idea...

[tensai]

I think nobody needs to ever use CMYK unless you're going to use offset printing. Inkjet with dye inks or pigment inks or most of the machines that photo labs use are all using RGB.
You often get better colour when your files are set in sRGB which doesn't make sense but the files set to the better/wider adobe 1998 RGB files print a little more flat and dull.

Don't expect to get 100% of what you see on screen. But you can get very close and if you want the best out of your file just make a test print, or a strip of 5 cm wide, check colours and make adjustments to fine tune.

cheers

[Elwell]

I think nobody needs to ever use CMYK unless you're going to use offset printing. Inkjet with dye inks or pigment inks or most of the machines that photo labs use are all using RGB.
You often get better colour when your files are set in sRGB which doesn't make sense but the files set to the better/wider adobe 1998 RGB files print a little more flat and dull.

The biggest market for these machines is general consumer use (i.e printing out snapshots etc), so they are optimized to work with the most common default settings and formats. For pretty much everybody except professional photographers/artist/designers, that's going to be sRGB.

[iambanana]

So your final verdict? CMYK or RGB? The battle rages on. The legendary battle of colour modes.

[Elwell]

RGB unless it's going to be printed four-color offset.

[Black Spot]

What about animation?