Using images from web for print - can it be done?

[mistercitizen]

Obviously, there are some copyright issues assosciated with this question, but my query is primarily technical.

Using a large image from the web, converting to CMYK and downsizing the image area until the resolution is 300dpi, would this be OK for print?

Are there any problems with this method?

 

[Evegenia]

It should be OK.
Your colors might change when converting from RGB to CMYK.

 

[duncdude]

yes they'll be fine - just that it's usually that the pics end up being too small to be of much use as they shrink down by a factor of 4 (300 dpi / 72 dpi = 4.16). I often use the pictures at 200 dpi and they are still fine. No one ever notices - unless you tell them... then they pretend they knew all along!


Kind Regards
Duncan

 

[mistercitizen]

200 dpi still prints OK?

 

[Eggles]

>>200 dpi still prints OK?<<

On a desktop printer, you'd be hard pressed to pick the difference between 200 dpi and 300 dpi. You might get away with an even lower resolution, depending on the quality of the printer. However, for offset printing, 300 dpi is usually necessary.

Also for desktop printing, there's no need to convert to CMYK - the printer will do that for you and you will probably get better colour anyway (brighter than CMYK). Of course, CMYK is still necessary if the material is to be offset printed, as they need to make separation plates.

 

[duncdude]

Eggles

Please tell me how you can get "brighter than CMYK" out of a printer that uses CMYK inks to print with?


Kind Regards
Duncan

 

[Eggles]

When the conversion of RGB to CMYK occurs in the authoring software, for some reason the output (printed) colours are often duller than if you had sent the data as RGB to the printer. It must be that the RGB->CMYK conversion that occurs within the printer (via the 'Lab' colour mode in many cases) seems different to what occurs in say, Photoshop. All I know is that if I send a RGB to print on a Xerox Phaser (colour laser) I get better output than if I send it already converted to CMYK. Try it yourself if you have access to a colour printer (also seems to happen with inkjets as well as lasers). And I am not just referring to printing on special photo papaer - I have seen it when printed to ordinary copy paper.

 

[Eggles]

I forgot to add - the CMYK inks used in desktop printers are a different formulation to those used in offset presses - and they really are brighter.

 

[duncdude]

Well that really depends on the individual companies who make the ink. The alliance formed with Epson (printer & ink manufacturer), 3M (manufacturer of stock for 'Matchprints' - similar to DuPont's Cromalin) and EFI (Electronics for Imaging - creator of RIP's) was formed to take proofing into the future - i.e. with no film involved. It would have been pretty stupid for them to be using ink that is too vibrant. And this is all ink-jet technology - as is the very expensive Digital Cromalin


Kind Regards
Duncan

 

[Eggles]

Duncan

I'm not going to get into a pissing match with you about this. It may very well be that at some point in the future what you are saying is true - better correlation between inkjet and offset inks. I am talking about NOW, and my experience with printing a variety of publications to both HP inkjets and Xerox Phasers is that you get better colour if the images are sent as RGBs instead of CMYKs.

 

[duncdude]

I just get twitchy when I hear statements like that. It's obvious you are not saying what I thought you might be. I've heard many things in the years i've been involved in pre-press. Like scanners scanning in CMYK... with no understanding that colour conversion is being done within the scanner. They would NOT send any scans to anything other than a high-end drum scanner BECAUSE they thought the scans were done differently.

I didn't mean to offend you!


Kind Regards
Duncan

 

[Eggles]

Duncan

Perhaps you did misinterpret what I said in the following quote:

>>Also for desktop printing, there's no need to convert to CMYK - the printer will do that for you and you will probably get better colour anyway (brighter than CMYK).<<

Perhaps I should have said 'brighter than if you had sent the images to print already converted to CMYK', but I thought that was covered in the previous paragraph. I am well aware of the the differences between CMYK and RGB whether on monitors, scanners, digital cameras or printers.