Photoshop help

[theyork]

i am submitting images for a book publication. my portfolio is saved at 300dpi, 12in by 8in.

they require images at 400dpi 6in. by 4in.

can i safely alter the size of these to match their specs without losing quality? how are you supposed to know? i realize generally you don't want to raise the dpi from its original setting but who the hell has images saved at 400dpi? i also have some old photos that are 72 dpi, but they are 59in. by 39in. can i jack these up to 400dpi 4in. by 6in. and not diminish quality.

is there some sort of guide or chart to guide one through this dpi vs size relationship?

[vizualizr]

The print world gets really jacked up about dpi - here's an easy way to resolve it.

12x8 at 300 dpi = 3600 pixels by 2400 pixels

6x4 at 400 dpi = 2400 pixels by 1600 pixels

So in truth - what they're asking for is actually a lower resolution than where you have your portfolio built at.

ProTip - when resizing them in Photoshop, first make a copy so you don't overwrite your original, then using the image size dialog, use "BiCubic Sharper" as your resampling method.

Is that enough clarification? Its super confusing, but if you just view everything as straight pixels, and the 300/400 dpi thing purely as a ratio used for print, it makes it a lot easier to understand.

i am submitting images for a book publication. my portfolio is saved at 300dpi, 12in by 8in.

they require images at 400dpi 6in. by 4in.

can i safely alter the size of these to match their specs without losing quality? how are you supposed to know? i realize generally you don't want to raise the dpi from its original setting but who the hell has images saved at 400dpi? i also have some old photos that are 72 dpi, but they are 59in. by 39in. can i jack these up to 400dpi 4in. by 6in. and not diminish quality.

is there some sort of guide or chart to guide one through this dpi vs size relationship?

[guitarchitect7]

Pretty much explained before. You're in fact reducing image quality because your lowering your dpi for your image.

I also concur to make a copy. I do this with my photos. I have my RAW image, my Proofs (full resolution) and my compressed.

Also, don't save down a jpeg, reopen, and save down again. You lose quality just by that process. Try to only save down to your final jpeg once. Or use TIFF and increase your file size by 10x.

[theyork]

The print world gets really jacked up about dpi - here's an easy way to resolve it.

12x8 at 300 dpi = 3600 pixels by 2400 pixels

6x4 at 400 dpi = 2400 pixels by 1600 pixels

So in truth - what they're asking for is actually a lower resolution than where you have your portfolio built at.

ProTip - when resizing them in Photoshop, first make a copy so you don't overwrite your original, then using the image size dialog, use "BiCubic Sharper" as your resampling method.

Is that enough clarification? Its super confusing, but if you just view everything as straight pixels, and the 300/400 dpi thing purely as a ratio used for print, it makes it a lot easier to understand.

should the "scale styles" be checked or unchecked

[vizualizr]

Scale styles won't matter if its just a flat image. If you have anything built with layer styles (drop shadows, etc), then check that box. Prior advice on saving as TIFF as opposed to a jpeg is also sound. At those sizes, TIFF will be manageable. If they insist on JPEG, use Quality=12. PNG files are also lossless (no compression artifacts).

[theyork]

Scale styles won't matter if its just a flat image. If you have anything built with layer styles (drop shadows, etc), then check that box. Prior advice on saving as TIFF as opposed to a jpeg is also sound. At those sizes, TIFF will be manageable. If they insist on JPEG, use Quality=12. PNG files are also lossless (no compression artifacts).

question about tiff

back in the day when i had work shot i would:
1) open them up in photoshop (they started out as JPG's from the photographer)
2) edit out dust, change brightness, contrast, levels etc. to sharpen them up
3) save them at highest quality jpg i could.

can i now go Back into these saved/adjusted files and convert them to TIFF? or does the original file from the photographer have to be in TIFF format?

[guitarchitect7]

question about tiff

back in the day when i had work shot i would:
1) open them up in photoshop (they started out as JPG's from the photographer)
2) edit out dust, change brightness, contrast, levels etc. to sharpen them up
3) save them at highest quality jpg i could.

can i now go Back into these saved/adjusted files and convert them to TIFF? or does the original file from the photographer have to be in TIFF format?

You can save anything down as TIFF anytime you want. I start out as a RAW file, and can save as TIFF at anytime.

Ideally though, you would want the original untouched file to be TIFF as that will contain the most bytes of information without artifacts for compression. Since you've already opened, edited, and resaved a jpeg, you're not gaining by saving TIFF now.

[theyork]

You can save anything down as TIFF anytime you want. I start out as a RAW file, and can save as TIFF at anytime.

Ideally though, you would want the original untouched file to be TIFF as that will contain the most bytes of information without artifacts for compression. Since you've already opened, edited, and resaved a jpeg, you're not gaining by saving TIFF now.

true, i won't 'gain' anything by doing it. however, if i save as tiff now i won't be 'losing' any information in the future by opening files later correct?

i would think this may be important because EVERY time i submit for a publication or show, every one of them has different specs on what image size and dpi they want.