Printing at 250 dpi

[JohnT]

I'm preparing an image for printing at 16x20, 8x10, and 4x6, all at 250 dpi. Do the figures in the fields below look right? The pixel dimensions look too large to me, but maybe not.

[jeffkohn]

You should use Bicubic Smoother instead of regular Bicubic. Bicubic Smoother was specifically designed to avoid some of the interpolation artificats you typically can get when using Bicubic to upsample.

What printer are these going to be output on? 250ppi seems rather arbitrary. You're better off feeding a Canon 300ppi, and 360ppi for Epson (although 288ppi is also OK according to some).

[johnastovall]

Originally Posted by jeffkohn

You should use Bicubic Smoother instead of regular Bicubic. Bicubic Smoother was specifically designed to avoid some of the interpolation artificats you typically can get when using Bicubic to upsample.

What printer are these going to be output on? 250ppi seems rather arbitrary. You're better off feeding a Canon 300ppi, and 360ppi for Epson (although 288ppi is also OK according to some).

Interestingly, Kelby in his book "THE PHOTOSHOP CS2 BOOK For Digital Photographers" suggests using Bicubic Sharper for large upsizing in a single step.

[JohnT]

Originally Posted by jeffkohn

You should use Bicubic Smoother instead of regular Bicubic. Bicubic Smoother was specifically designed to avoid some of the interpolation artifacts you typically can get when using Bicubic to upsample.

What printer are these going to be output on? 250ppi seems rather arbitrary. You're better off feeding a Canon 300ppi, and 360ppi for Epson (although 288ppi is also OK according to some).

I'm ordering from Mpix, and 250 is what they recommend. However, I'll go higher if it will result in a better print.

[Bartman01]

MPix recommends 2000x1600 or higher for a 20x16 print. If your image is at least that size, I wouldn't bother up-sizing it since their machine will do this for you and will probably do a better job than you can. I would call them and ask what their recommendation is for your specific situation. They will be in a better position to tell you what to do.

[JohnT]

Originally Posted by Bartman01

MPix recommends 2000x1600 or higher for a 20x16 print. If your image is at least that size, I wouldn't bother up-sizing it since their machine will do this for you and will probably do a better job than you can. I would call them and ask what their recommendation is for your specific situation. They will be in a better position to tell you what to do.

Thanks, Bart. I guess where I'm confused is the Document Size in the Image Size dialog. Should I just ignore the DS and work with the Pixel Dimensions and Resolution.

[Bartman01]

Originally Posted by JohnT

Thanks, Bart. I guess where I'm confused is the Document Size in the Image Size dialog. Should I just ignore the DS and work with the Pixel Dimensions and Resolution.

If the image is already 1600x2200 or larger ignore the 250ppi goal for now and call/email MPix before you do anything. Their machine should upsize the image for printing and will most likely do a better job than you can unless you know what you are doing, have specific requirements that they can not meet, or are printing something other than a normal image (like if you have added text to the image).

From whcc.com's FAQ for large file printing (A was edited to remove a confusing statement):

Q. For large prints should I really leave the resolution blank?
A.
We suggest the following: If it is a single image, similar to images you would deliver shot on film ... Our equipment will resample the image for printing. A good analogy to this is a balloon, when you resample the file at your end you are blowing up a balloon, making it larger and harder to deal with as it gets transferred to us. Leave the balloon flat and let us blow it up. On the other hand, if your image has text, is a multi-image panel print, or you want to sharpen and perform extra work on the image, please resample the image to the final size to insure sharp text and the best results. The difference is these computer-generated modifications make use of the extra resolution, while the original single image would not.

I imagine MPix would say something similar if you called them.

[Bartman01]

Forgot to add: if you do decide to upsample the image, do some searching for the different processes. There is more than one way to do it, but Adobe currently recommends (for CS2) a one-step upsample using bicubic smoother.

[JohnT]

Thanks, again, Bart! This really helps.