i just don't GET IT!

back alley

back alley

IMAGES
Local time
2:54 PM
Joined
Jul 30, 2003
Messages
41,288
Location
true north strong & free
View My Gallery
i'm trying to get a print prepared for the print swap.

knowing that i don't really get it when it comes to scanning and print sizes i thought i'd ask the experts, so i went to the lab that will be printing my end file.

i looked at some of their work when checking out different papers and i was very impressed.

i asked about file size and resolution for printing.

they gave me a copy of some info, said that they print at 300 dpi and that hi res scans can be up to 18mb for prints up to 11x14.

so i work on my scan, clean it up in photoshop.
when i go to save it i downsize the resolution to 300 dpi and change the size to 2700 pixels on the long side. my file size is 2.75mb.

does this sound right, will it make for an acceptable 8x10 print or 11x14?

some day i will read something or someone will explain it to me in words that sink in and make sense.

much appreciated,
joe
 
Your pixel dimensions sound right -- if your image area is 7 x 9 inches at 300 pixels per inch, then your file should be 2100 x 2700 pixels.

What's wacky is your file size: 2100 x 2700 pixels is 5, 670,000 pixels (that's 5.67 million) and if we assume it's an 8-bit grayscale image, each pixel will require one byte to store. So, you should be coming up with about a 5-point-something-megabyte file for grayscale; if you save it as RGB (which some people like to do for tone control) then you'll need three bytes per pixel, which gets you up into that 18-megabyte file size territory you've heard mentioned.

Since your files are smaller than that, it suggests that you're saving them in a format that applies compression. That's no problem if the compression is lossless (TIFF files, for example, have a lossless-compression option) but if you're using JPEG, then that's "lossy" compression -- some of the data actually is thrown away to make the file smaller.

You can still make a high-quality print from a JPEG file if the compression isn't too extreme, but I'd suggest you try making a print from the original uncompressed file and then another from the JPEG-compressed file and compare them, just to make sure you're satisfied that you're not giving up too much.

Personal preference: Once I've gone to the time and trouble of scanning and cleaning up a negative, I like to save my original "master" file in an uncompressed format, just to make sure all the data stays there.
 
Last edited:
"Dots" and "pixels" mean the same thing as far as your computer is concerned. So
300 pixels/inch x 8 inches = 2400 pixels, and 300 pixels/inch x 10 inches = 3000 pixels. Therefore, in order to print an 8x10 at 300 pixels(dots)/inch, the pixel dimensions should be 2400 x 3000 pixels.

If you just give them the image at maximum resolution, and tell them you want an 8x10, their equipment should be able to do any scaling or resampling automatically.
 
the image is in rgb, that's what the lab calls for.
also it's a jpeg.

i had hoped to give them a finished file as they charge for any extras they may have to do.

maybe i'll put what i think they are asking for and one at full resolution also and they can decide how to proceed.

joe
 
Joe, unless it's HEAVILY compressed (like, say 10 times), the JPEG format is also fine.In Photoshop, if you go for quality"90" out of "100=the best" you should not see a difference, i think.

The math of printing is easy, nr of pixels needed is printing resolution (e.g.300 dpi, but can be lower if the print size is biiig) times size. For prints of 11x14 inch, you'll need thus 3300x4200 pixels ideally, but the wieving distance will probably be larger so you can get away with say, 250dpi prints too.
 
they prefer a jpeg file but will also do tiff.

thanks guys for your patience in this. i know i have asked similar questions in the past but math just escapes me (that's why i work with people) and just when i think i kinda understand it...poof..it disappears.

joe
 
Yeah, your results will be fine from a JPEG file as long as you use the highest-quality compression setting; from the file size, it sounds as if you are. For a 7 x 9 print (leaving 1/2-inch margins on 8 x 10 paper) your resolution and pixel count are fine, too, so there's no reason to send them a higher-resolution file (Why risk confusing the lab? That's always been my motto.)

One potential tip: Make sure the lab knows you INTEND for your print to have white margins around the edges. If you don't tell them this, some printing machines automatically scale your image to make a full-frame print. This will reduce your sharpness slightly (because the machine does math on your pixels to make them fit) and will leave you with a print with borders along one side only (because 7 x 9 and 8 x 10 aren't exactly proportional to each other.)
 
It just seems that you're looking at the compressed file size, and the lab gave you the uncompressed size. Open the jpeg in Photoshop and look at the file size on the bottom left of the window - that will show the uncompressed size, which will probably be around 18mb +/-.

Rob
 
So you're not too far off - just increase the dimensions. Forget the math and what's logical, make the long side around 3500. That might make it too big, but you can play with it.

Rob
 
too late.

i just sent off both files for printing.

gotta love this internet, i scan the negs and do the photoshop thing and then email off the files for printing.
they will contact me when done and i'll pick them up.

i will see the results and ask their advice also and make changes as needed.

many thanks folks, one day i will understand...

joe
 
backalley photo said:
they gave me a copy of some info, said that they print at 300 dpi and that hi res scans can be up to 18mb for prints up to 11x14.
Click to expand...
Dude, I am soooo with you. I get sooo freaking confused with a lot of this. And I'm in the IT field!! So much easier to go to the store and get 25 sheets of 11x14 paper, choose a 35mm negative, and make a print 🙂

I'm following this thread though and taking notes. I need to learn this stuff so I won't look so dorky when my kids ask me.
 
Last edited:
ok, a bit of an update.
as i stated above, i sent off 2 files for printing, one was saved as a tif and the other as a jpeg.
i asked for 8x10 prints on glossy paper.

i picked up the prints earlier today and i have to say they look pretty good. i like them both and if i didn't have them side by side i would be satisfied with either.

that being said, the tif print has more edge sharpness to it and overall a bit more snap.

these are the first prints i have had done from a digital file.
my earlier worries about file/pixel size etc. can be relaxed for now.

i may have this same tif file printed at 11x14 next to evaluate that.
it's doubtful i would go larger than 11x14 for the most part.

there is still much to learn though...

joe
 
This is a hijack (everybody against the wall)...

On the subject - is there anything I can do with my scans ahead of time to ensure maximum chance of the lab getting it right? Greyscale vs RGB, if an image is cropped, how do I maintain my image without getting cropped to fit 4x3 aspect ratio and losing something I wanted, etc... Any flags or settings I can do to keep them from tweaking levels beyond what I've already done, etc...
 
ok, complete idiot here!!!!!

my intent when getting 2 of the same neg printed was to compare the differences (if any) between a jpeg and a tif file.
i was so intent on looking at the details that i missed the whole.

the lab cut off the top & bottom sections of my print.

i had picked the shot of the door with all the condensation, with the reversed words 'please use side door' - they cut off the 'please' completely!!

i'm guessing that i should have gone with an 8x12 sized print.

joe
 
That's what I was warning you about in my previous post, the one about telling the lab that you want the image printed dot for dot and you expect it to have white borders all around.

They were trying to size the image to one dimension of the paper, and did it by cutting off the other dimension.

If you want your print on an 8x10-inch piece of paper, you should set your CANVAS size to 8 x 10 inches, and then position the IMAGE within that so you get the borders you want. Then instruct the lab to print the full image, including the borders.
 
You must log in or register to reply here.

Similar threads

T
I am looking for a new multi-function home printer
Replies
7
Views
542
Tim Murphy
T
L
Help a commoner!
Replies
11
Views
501
Formerly presspass
F
raphaellehnen
New zine! 'Carry That Weight' and the limitation as a catalyst for creation.
Replies
1
Views
194
robert blu
robert blu
B
17"x22" Ink Jet Prints vs. Original Max Resolution Digital Files
Replies
6
Views
485
boojum
boojum
Ray Kilby
Bought a cheap lens for the hell of it and gave it a go.
Replies
7
Views
435
Ray Kilby
Ray Kilby
Back
Top Bottom