View Full Version : Size reduction, part 2

04-05-2003, 08:14 PM
Hi. My name's Tommy and I'm computer retarded.

I'm scanning art images for viewing on the web, and need advice on reducing images. How many dpi should I scan at, and how much should I reduce it? I've been told around 100-150k is good for the average image, is that right? The program I use for art lets me reduce to a percentage.

04-05-2003, 09:23 PM
alright, i checked in my sketch magazines and found an article on it. It said that you should scan at 600 dpi then go down to 300 dpi. It also said that if you want to go higher or if it makes you go higher than 600dpi to begin with that thats fine too.
hope that helped,

04-05-2003, 10:20 PM
It really depends on what you plan on doing with the image. If it's just for viewing on the web, you can get away with as low as 150 for gray scale at roughly 600px wide. I generally do 300 for both gray and color, on an 11x17 board that gives me a pic over 2200px tall, reducing it to 600px wide (ratio the same) gives an image well suited for web viewing.

If you're looking to get someone to ink or color a pic for you later, definitely go with s.s. and stay with 600dpi, but remember that will generate an enormous image and depending on your PC, will affect the scratch memory in photoshop a lot the more you work it.

Good luck, let us know.

Tony Moore
04-06-2003, 05:39 AM
Basically, i almost always scan at 600 dpi, unless it's just a quick scan of a sketch or something. then once it's scanned, depending on what i'm using it for, i'll adjust the resolutions accordingly.

Here's the deal with resolutions, depending on what kinda image you're dealing with:

for the WEB___________________

black and white web images: 72dpi 8-bit
Monitors display at 72dpi, so that's what most people use. really and truly it doesn't matter, just so long as you keep the dimesions at an easily viewable size of no more than 600 pixels wide. it's best to use 8-bit for this, because the greys will smooth out your lines when resampling to such a small resolution, but won't bother with unneeded color information that would make your file size unneccessarily larger.

Color web images: 72dpi RGB
Monitors display at 72dpi, so that's what most people use. really and truly it doesn't matter, just so long as it's in RBG, which is the color model meant for electronic display... and keep the dimesions at an easily viewable size.

and yeah. for either of these, it's best to try and keep your pics' file sizes down around 150K or less.

for PRINT______________________

black and white lineart: 600 dpi 1-bit
just plain inked lines reproduce best at around 600 dpi and when converted to bitmap. greys and antialiasing will make the reproduction fuzzy, the filesize unnecessarily bigger, and are for all intents and purposes unneeded.

black and white w/ greytones: 400 dpi 8-bit
these reproduce best at 300dpi or better. 8-bit is the greyscale mode, and indexes the full range of 256 observable greys. since i make my color files 400 dpi, it's just a habit to make greytoned files 400 dpi, also. best to have a bit of excess than too little when it comes to resolution, i guess.

full color print: 400dpi CMYK
much the same as greyscale, these reproduce best at 300 dpi or better. the lineart should be bitmapped before coloring, so the extra resolution helps keep the lines from getting chunky and pixelized.

i hope that helps.


04-06-2003, 11:04 AM
Ok, here's what I was doing:
scanning b & w art in grayscale for viewing on the web. The program I'm using is Photoplus4 (came with my computer, but it gets the job done!). I have Photoshop 6, but not comfortable using it yet. I scan at 300dpi, and fiddle with size reduction to about 25% until it's right. You can check the results here: http://www.lightbulbcomics.com/col1art.html
You'll notice that some of the images are hard to read (Pgs. 1-6) and file size is a little high.

So I should scan at 600dpi, and if I reduce it to 600pixels wide, is that good?

By the way, I appreciate all the help. I don't have much time to visit here, but anytime i've needed help, someone always jumps in right away! You guys are all right!

04-06-2003, 08:41 PM
Hey Tommy,
I can't help with the tech questions you have (i'm severly computer disabled) but I wanted to compliment you on the site.
Looks like you've been crazy busy man. Good stuff brother!
Talk later,

04-06-2003, 08:52 PM