One of the rules for artisanal submissions is to keep the file under 500k in size. I've been working on a piece for about a month and went through a lot of trouble to scan it properly. Best I can get it at without reducing quality is 867k... help? I really dont want to compromise picture quality for file size.

Does it utilize a lot of colors or few?

If it uses 256 or less, using a GIF format will compress by limiting the color palette rather than kicking out quality. I'm guessing, though, your best bet is to export as a JPEG and see what kind of compression you can live with. Also, reducing the actual dimensions of the file can help.

heh...more than 256. Lots of color. I can convert it to all sorts of file formats, .jpeg has been my best bet but its still over 500k in size. I could reduce the actual image size, but thats something I dont really want to do... Anyone know of any nifty little apps out there I could use to reduce the size without giving up quality?

Download this freeware.

Save pictures in this freeware, and it'll turn huge files into tiny files (like 100+MBs to 16kbs.) Lost a bit of resolution, but it still looks pretty good. I usually use this program to reduce the file size to submit my artisanals.

Yep, IrfanView is a great utility.

Your not going to have much luck in reducing file size without losing any image quality. Lossless compression, such as with zip/png files can only compress data so much. After that you are left with only two choices for file types. Gif is only helpfull for reducing files that use or can be made to use a limited number of colours (256) there are various methods of reducing an image colour count to 256 and the different methods can produce wildly different results in terms of image quality in comparison to the original. Gif is pretty useless for photographs or artwork involving any type of delicate shading etc. After that you are left with JPEG which is a lossy compression method. The more compression the more noticable the compression artifacts become. Play with irfan view and decide which level of jpeg compression you can live with. If the file size is still over 500k then you will have to resize the image.

Now I'm guessing at this point, (perhaps an admin can confirm?) but I would assume the judges will be viewing the artwork on a regular sized monitor anyway... not printing it out?? So a huge resolution isnt going to be a great boon because which ever viewing software the admins will be using will reduce the image size anyway to make the whole thing fit the screen. On-the-fly resizing done by viewers is much cruder than the resize/resample filters available in packages like PSP/photoshop/irfanview, so you might be better off resizing it anyway?

Image should not be more than 600 pixels wide, I don't think there is any reason for that. Also the issue of printing vs screen size is an issue of DPI not resolution. If made in Photoshop your images should not be more than 72 dpi.

72dpi is quite low considering current epson photo printers are able to print at 5760 x 1,440dpi... The quality of the print does depend on dpi (amongst other things such as toner/ink system used, printer firmware, colour profiles, printer driver, and type of paper) However, if I send in a 1600x1200 resolution image, and then a 800x600, you would need a magic printer to make the lower resolution image look as good as the first when printed out... The data is just not there. You either end up with a smaller version of the photo on the paper, or if you scale up the second image to be the same size on paper as the first, you get much poorer quality and more noticeable pixelation. For viewing on a pc, especially for a web page then yes 600 pixels wide is a reasonable res, but if you intend to print, then it is worth keeping the resolution as high as possible.

72dpi is screen resollution, not print.

Print should be 300dpi minimum.

Your example is incorrect. If you send me a 1600X1200 image with a dpi of 600 it will look exactly the same as a 800X600 image with a dpi of 600. The only difference will be that the first image will take up half the page, but the smaller image would take up 1/8 of the page (or whatever the math turns out to be)

Resollution = size Dpi = quality.

However, on a Computer, dpi is always 72 (or lower) and so on a computer the larger the size the better the quality looks.

So to answer the orginal question...

Scan your image in as large as possible. 1600 dpi if possible. you should get a nice 5mb file.

After you scan it, bring it into something like photoshop and drop the dpi down to 72. And shrink the dimensions by no more than half (even if that ends up larger than 600 pixels... if you reduce by more than half it starts looking blurry) Then you should have it below 500k

First:

Save your image as a GIF, PNG, or JPEG. The only way to know for sure is to convert into all three formats and then check the size. Running pngcrush on a png file can reduce its size a lot, as well, without loss of quality - For example, the test image of Lenna, when encoded 'naively' with ImageMagick, is over 30% larger than the same image after pngcrush. Both GIF and JPEG can reduce the quality of your image, and more often than not will; PNG won't. As GIF is limited to 256 colours, it is hopelessly inappropriate for any sort of artwork that doesn't rely mostly on flat areas of mostly uniform colour. JPEG will produce artifacts and graininess. I suggest you save to PNG unless you can get significantly smaller images of equivalent quality with JPEG or GIF.

Then, scale the image down. Generally speaking, an 800x600 image is fine for judges, but you'll want to make it as large as you can while staying under the 500K limit.

thanks for the tips guys, got it under control. ^^