TinMan opened this issue on Aug 08, 2000 ยท 20 posts
Daffy34 posted Tue, 08 August 2000 at 10:51 PM
Okay kiddies. I'm gonna clear this up once and for all. Just let me start by saying that I am a graphic artist by trade and have been for almost 8 years. I'm gonna try to make this explanation easy to understand for people who don't quite know how this works...I have to do it nearly every day to customers on the telephone. I work for a magazine and so I'm gonna explain what resolution means to us, who have artwork printed at a professional printer. First off, the whole business of printing on an injet kinda defeats the purpose of going to a printer to have your image printed in the first place (unless of course you don't HAVE an inkjet). I make an image at home 1024x768 pixels. I don't even run it thru Photoshop...I just print it directly to my inkjet (which is 1200x1200 pixels). It prints pretty darn nice. It looks a little pixelated, but all in all pretty decent. Of course the image was only 72 dpi because I didn't change the "pixel resolution" in Photoshop. It's also very large. Why does it look good you say? Because contrary to popular belief, injets do not apply the same technology as a 4 color press. On an injet, the printer sprays all 4 colors on the paper at once. It uses a more scattered pattern than a 4 color press thereby breaking up the edges of the pixels that you would definitely see on a 4 color press print. A print made on a 4 color press is passed separately thru the press for each color and each color dot is placed "on top" of the color before it. Since the pattern is not scattered, the pixels will show at only 72 dpi. Our magazine, for instance, requires that every image in a camera ready piece be AT LEAST 300 dpi. Anything less than that will look "soft" (slightly blurry if you like) and at resolutions less than 200, will look downright awful. Pixelated, grainy, bitmapped, crunchy...however you want to phrase it. You can take a 72 dpi picture and make it 300 dpi in Photoshop and increase the resolution...however, it will make the image fractionally smaller than it was before. Think if it this way...72 dpi as an ink dot the size of a pencil eraser and 300 dpi as an ink dot the size of a pin tip--72 dpi eraser size dots 1 yard apart and 300 dpi pin tip size dots 1 micrometer apart. Finer is better. You can resample the image in Photoshop and increase the pixel resolution without changing the size; however this will give you unsatisfactory results because Photoshop has to "guess" what information to put in the same space where there is no information originally. That's why you can resample in Bilinear, Bicubic or Nearest Neighbor...it will use a different formula for each, none being really satisfactory. The ONLY way to increase the pixel resolution of an image in Photoshop and keep the original integrity is not to resample the image at all, which of course makes the original image much, much smaller. So, to make a long-winded story short, your original image must be rendered at a very high resolution (at least 3000x3000 pixels) to be a decent size when printed at a resolution at 300 dpi (in an inkjet 300 dpi doesn't sound that great and it isn't...on a 4 color press, it's quite sufficient). Pick up any magazine that has decent color printing on decent paper and I'll guarantee that it's printed at at least 240 dpi. I hope this helps...it really isn't easy to understand for folks who don't really need to understand it. I have a hard time explaining it to my customers who just don't understand that we can't use a picture off of their website that is only 72 dpi and only 2 inches by 3 inches in size. How do you make them understand that we can use it, but it will print at less than the size of a postage stamp? All the layman needs to remember is this...when rendering to screen resolutions (72 dpi) render as large as possible if you want a decent sized printed copy because it will get smaller. And Arcady is exactly right...it will take you forever to render at those dimensions in Vue; you will have to do it in stages. A sad but true fact in 3D unfortunately, unless you own an SGI workstation. :) Laurie