Doubling image size for print….Half the DPI? Or Interpolate at full DPI? Which looks better?

SP
Posted By
Sid_Phillips
Jan 2, 2008
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433
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5
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Closed
Scott:

Since there haven’t been any posts in a week I guess you figured out that Onyx is a printer RIP that can up-rez images as required for printing large-format from small(er) files.

If you up-rez at all – no matter who’s software you are using – you are adding fake data. That’s how up-rez works, it is image interpolation. To use your enlarger analogy, you would print the file as-is, no resizing in PS and no resizing in the RIP. That’s the only way to print large without interpolating. (Note: most RIPs and printer drivers either up-or-down sample to the printers native image resolution.)

And if people are going to be compelled to examine your large images up close, you need to start with images sized appropriately. Not always possible, I know. But data is data. Either it’s there or it isn’t. If it isn’t, then you gotta fake it or do without.
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AV
Andrew_VanHausen
Jan 3, 2008
Something I have experimented with, and seen good results with. If you do have to add actual pixel size to an image, do it in small increments, say 5% to 10% at a time, rather than simply typing in transform to 200%. The results were indistinguisable from an image that was taken at the proper resolution (we used a digital camera and high and low rez images) and we were using sub-dye photo printers. I don’t remember how much we had to bump the low rez images to match the high, so beware of when this effect tops out, but it does allow some actual adding of image size.
JJ
John_Joslin
Jan 3, 2008
This has been shown to have little advantage compared with the results of Photoshop’s latest resampling algorithms.
B
Buko
Jan 3, 2008
If you do have to add actual pixel size to an image, do it in small increments, say 5% to 10% at a time, rather than simply typing in transform to 200%.

Wrong!

This might have been the way to go with Photoshop 7 and earlier, but as John mentioned, since CS the new resampling algorithms make stair stepping unnecessary. in fact it adds more artifacts.
P
Phosphor
Jan 3, 2008
In my opinion, NCIS is a much better show than CSI.

Paulie Perrette!
P
pila
Jan 5, 2008
There is no way to enlarge number of pixels withoug significant loss of quality. Exceplt for the CSI version 🙂 as stated before me. You are inventing data which does not exist.

I never upsize. No point, you can not improve inventing the data. As for which is better, try it for yourself. Make all the variants you are interested in, and then, calculate how much pixels and PPI you need from each version to produce say 13 x 18 cm picture (giving a crop from the full size picture). And make several 13 x 18 cm pictures which are very inexpensive. And see for yourself!

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