View Full Version : Resolution and Computer Lag workaround
01-13-2006, 01:25 AM
Hi all, I posted this in the PAINTER forum on Conceptart.org too so sorry if you see this twice, but it applies to both Painter and Photoshop I'd say so I thought Id pick the brain of all you CGTalk peeps too. I tried a search on this topic but the keywords I use always get a result of about a million posts none of which seem to be specific about what I am asking, heheh, so sorry if this has already been addressed somewhere.
Basically I am wondering if there's a resolution trick for working in print quality but are having speed issues on the computer. I am basically doing comic book inking-style lineart over my sketched layouts in Painter (sometimes photoshop too but I like rotating the canvas too). An original page, hardcopy, is 11x17 and print res. is 300dpi of course. But the problem is, working on an 11x17 300dpi file tends to really lag my computer sometimes.
Is there a trick or something I could do to get around this, such as working at a bigger size but lower dpi or something? But then how would I resize to be print-ready. I thought maybe that could work but then it doesnt get smaller in pixels when I change to 300 dpi, it actually raises the pixels. So of course that's not working. Any other ideas? Or am I just screwed till I get a faster computer?
01-13-2006, 03:17 AM
I thought maybe that could work but then it doesnt get smaller in pixels when I change to 300 dpi, it actually raises the pixels. So of course that's not working. Any other ideas? Or am I just screwed till I get a faster computer?
It sounds to me like you need to uncheck the box labeled "resample" in the Image Size dialog in Photoshop - the pixel dimensions of your image should not change. That said, I don't think it will speed anything up - you can always try it and see though.
01-13-2006, 05:18 AM
Ill have to check that. So if I did that though, say I have a file that is hypothetically 1000x1000 pixels. If it works ok, speedwise, at 150dpi at 2000x2000 pixels, then would that be the same as working in 300dpi at the original size of 1000x1000? And if so, how would you resize correctly for sending to print for the original size of 1000x1000 pixels?
01-13-2006, 05:32 AM
Just to be a bit clearer too, heres a small sketch I inked in the style that I am doing for the bigger images. This was even a bit slow at 300dpi and its like 2.5 inches or something whereas the actual work I'll be doing is 11x17inches.
But the problem is, working on an 11x17 300dpi file tends to really lag my computer sometimes.
Is there a trick or something I could do to get around this
no tricks...your running out of ram...thats the only solution. Assuming though your only workin on black and white, try working in greyscale mode which will shave a lot of ram overhead off.
And if your producing line art images like the one above right then you should be aiming for a resolution more like 6-800 dpi at print size.
01-13-2006, 10:17 AM
Really?!?! I thought all print was 300dpi.
01-13-2006, 11:15 AM
Oh I guess not for lineart like that. Been readin up on some other threads.
yes...its a bit compex, but as you make an image using more contrast and detail you need to increase the res.
this is why type isnt done at 300dpi, cos it looks fuzzy...its not enough res.
300dpi is enough for most contone images (continous tone)....rule of thumb for res at print size = 2 x line screen ruling (lpi)...type and line art aren't considered contone because they tend to be made of solid colours rather than tones or shades.
1200dpi is enough for most lineart images (no mid tones whatsoever, no greys, no antialiasing, no shades) rule of thumb for res at print size = 4 x line screen or even better the optical res of the image setter.
as your making a contone image (you've still got antialiasing) thats close to lineart you need to work somewhere in between...750dpi.
of course, if you use a lower screen for print you can drop those figures...and working in greyscale saves a hell of a lot of memory (just one channel needed). Also as you lower the sceen ruling you can also move further away from the ideal 2 or 4:1...so for a 100 lpi image you could get away with 150dpi perhaps if it was a continous tone image with low detail or contrast.
One day i'll post a sticky with the science behind it. :)
01-15-2006, 08:38 AM
woah, thanks Halo, that helps bigtime! WOuld love to hear more of the science behind it sometime but what you said defintiely helps it make a bit more sense to me. Looks like Im up-resing BIGTIME! (is up-resing a word? heheh)
i've got it in my head...just need to re-work out the finer points and then i'll write a post about it.
01-15-2006, 10:33 PM
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