Printing large files

[tonysab]

This will probably seem like a really dumb question, but I'd appreciate any advice. I take digital pics on a 4mp camera at full resolution (2200 x 1700 pix approx). When I come to print on my Epson 830 I always print the whole image and specify "fit to page", on the assumption that printing at full size will give me a better quality print.

My question though is, is this really true. For example if I print as per the above onto 11 x 8 paper, is that going to give me a better print than if I resized the image to 11 x 8 first, and then printed that? I guess that at some point some information in the picture is discarded but does it make a difference whether it is the printer that does it, or the image editing software, as per my outline above.

Thanks in advance,
Tony

[Dirtdarte]

If you are printing 8x10 with a 4mp image file, your resolution will be plenty without resampling up the image.

If you crop the image and then print it at 8x10, you may run across some problems.

The important thing to remember is your eyes can only see about 250dpi resolution so it isn't important to print at anything higher than that. I commonly print at 300 dpi. Just make sure your image file is at the proper resolution.

[BigAl]

I wouldn't use the "fit to page option", as you're relying on the printer driver to do the scaling. If you want to resize, use the resize image dialog in your image editing software.

Also, in the resize image dialog there is an option to resize the image without resampling - in other words all the pixels are sent to the printer. I can't remember what the option is in PS, but in PSP you uncheck the "Resample using" box. This is useful as you always retain all the pixels.

[svsg]

If you are printing 2200x1700 pixels on 11x8, you are effectively giving only 200ppi to the printer. I remember reading that the photoquality is about 300ppi at the final printing size. So I would think that you should consider printing on a smaller area(say 8"x6") to get the best quality. And another point(not to confuse you), the dpi that printers specify(something like 2000 dpi etc) are different from the ppi(pixels per inch).Actually what matters(relatively) is ppi. The printers use many dots to make a pixel. And if you stuff in more than the required number of ppi, the printer has to discard some of it or use some algorithm(which we may not know) to get lesser number of pixels to print. So you can resample the image to give the printer only the required ppi to print photo quality.

[kaulike]

Specifying a print size when printing just means you are asking the printer driver to resize your image automatically. That's not necessarily bad; it is one of the jobs of the printer driver. Whether or not it is the best thing to do depends on your other options.

If you are comfortable with Photoshop, Paint Shop Pro, or similar high-quality image manipulation software, you can possibly resize/resample more intelligently by hand than the printer driver can. You can certainly fix flaws in the image, where the driver can not.

If you are depending on the default behavior of your image software, then I doubt you will get any better results than by just using the printer driver to do the same thing. Both use similar algorithms to resize.

In short, if you are happy with the results, don't change what ain't broke!

The best advice is to do some tests and find out. Try resizing with software and then printing at 100%, and then print using the printer driver's "fit to page" option. Just for kicks you might try upsampling a crop from one of your photos---take a crop and resize in Photoshop (or whatever) at 200% using a bicubic algorithm, set it to 240dpi, and see what the print looks like.

Also, 200dpi may very well be photographic quality on an inkjet printer---it depends on the image content, and on your personal standards. Digicam images upsample much better than the average scanned image in my experience. I wouldn't worry about it, though of course you will have much more control upsampling yourself than asking the printer driver to do it for you.

Finally, I highly recommend reading some good books on image manipulation. The Real World books are outstanding, though very technical, and the ones by David Blatner (Scanning & Halftones, Photoshop 7) discuss printing processes in excruciating detail.

Best,

Jeff

[slipchuck]

my input

when I want to change the size of the photo from a digital image I open it up full resolution from your camera.
I then use the crop tool and put in the exact size you want to make the picture to.
Now when you make the selection it will make the size of print you wanted no matter how big or small you make the selection box.
on the printer I put the size of the paper you use to exactly the cropped picture you made.
if the paper is bigger then the print you want just choose center the image on one of the choices you have.


hope this helps.

P.S if you pre-crop all your photographs (example 4x6) before you send them to a lab you have control were the picture will be cut off...sometimes the labs choice is not the one you wanted!

slipchuck