300D resolution > print equivalent? (inches)

[piku]

(LF) 3072 x 2048 3.1MB > ?
(MF) 2048 x 1360 1.8MB > ?
(SF) 1536 x 1024 1.4MB > ?

also, most of my friend would like to print pics--whats the best resolution (to crop with in PS/CS) do you guys and gals recommend for print? ...lets say for 4x6 and 5x7

TIA.

[Jesper]

What do you want to know exactly - what the maximum possible print size is? There is no fixed answer to that question. It depends on how picky you are with regard to quality.

One often quoted rule of thumb is that you need 300 pixels per inch to get really good quality photos. With that number, your list would look like this:

(LF) 3072 x 2048 > (3072 / 300 =) 10.24 x (2048 / 300 =) 6.83 inches
(MF) 2048 x 1360 > 6.83 x 4.53 inches
(SF) 1536 x 1024 > 5.12 x 3.41 inches

But these are not really fixed numbers. You should really make some test prints at different sizes with photos of different pixel dimensions and determine what you consider acceptable quality.

[piku]

those would do just fine as they are, as you said, "often quoted rule of thumb"

i opened one of my LF images (3072x2048) in PS, and i was going to resize it to a smaller res. i happen to notice that it stated "180 pixel/inch" which makes the LF res 11x17 prints on 180pixels/inch (medium quality if you would call it).

i'm just wondering about this stuff just to make it more efficient for me to publish pics on the web for my friends, but allow some great res. originals if they ever want to print a nice pic. so i guess, sticking w/ the LF res everytime aint bad.

thanks.

[robertwgross]

Mark me as a radical, but I never resize image files and I never touch any dpi settings.

I keep my original TIF files intact and pristine. When it is time to print, I let the print driver figure out what has to be scaled to hit the paper right.

If I need to publish some image to the web, then I simply resample the original TIF downward (like to 20% each way) or until I hit a file size of 1.0-1.5MB or until I hit a pixel size of 400-600 pixels on a side. Then I convert to JPEG with only about 20% compression. For the web, that yields a JPEG file of 50-100KB, which is a good viewable image. Resampled JPEG files are kept in a different directory from the original TIF files.

---Bob Gross---

[dsze]

Yes, I agree, except I keep the original RAW file instead of the TIFF. If I do alot of post proc. work then I'll keep the TIFF as a master or I'll even keep the PSD image, but in general I have a hard drive full of RAW files.

-daniel

[robertwgross]

I keep the RAW file archived away, since I can't fool with it anyway. I think of it as the digital equivalent of a film negative. Those are copied onto removable media, and only the TIF and sometimes a JPEG will remain on the hard disks.

---Bob Gross---

[dsze]

So, why don't you just keep the RAW on the HD? I too think of it as the digital negative, but with PS CS being able to browse the RAW files as fast or faster than the TIFF's, it just seems easier to keep the RAW. I guess partially so because I am still learning at a very fast rate and I am always finding myself going back to the RAW to process the same photo a little differently when I learn a new method. The RAW files tend to be a bit smaller than the TIFF's too don't they? I find myself processing differently from RAW to TIFF for the same image depending on what I'm doing with it. For example, if I'm doing a B&W I'll process it differently into a TIFF than if I'm doing the same photo in color, or sepia, etc.

When my HD starts getting full, I'll burn the RAW files to DVD, but that may be awhile. I've got 120GB just for photos. As cheap as hard drives are now, its almost easier to keep buying HD's rather than burning to DVD, CD, etc. :)

-daniel