Blowing Up Digital Photos

DLL_4ever · Nov 5, 2005

I want to blow up some of my photos, and i want them to be big. Somewhere around 24 x 18 (inches). Perhaps even bigger once i get the measurements right.

My first question is (this is directed mainly to the Canadians here), where can i print photos this size? I tried Blacks and other photography stores, but they can only do up to 10x8.

My 2nd question is, how will a digitally-made photo look when blown up to this size? Unfortunately i was stupid enough to resize all of my photos to 800x600, without saving larger copies of them. How will these photos look when blown up? Will they look the same as if you were to resize them using photoshop?

Thanks in advance!

craig · Nov 5, 2005

I like to think of photos as enlarged as opposed to being blown up. Check local prepress or press outfits. Generally they have printers that go 25 x 36 inches and beyond. The file size will need to be large. 800 x 600 pixels will not make for a good enlargement.

Meysha · Nov 5, 2005

800x600 will give you an awful print. Worse or better depending on what dpi you saved them as.

Ideally you want 300dpi when printing things. If your photos are saved at this resolution (which I doubt) then you could probably (maybe if you're lucky) get a 5x7.

DocFrankenstein · Nov 6, 2005

Meysha - dpi has nothing to do with it. If it's 800*600 you're going to be REALLY bad enlargements.

Costco makes 18*12 as their largest size for 4 bucks a pop... I use them a lot

I also use these guys. Very good service. Friendly and professional.
http://photocentre.ca/?help

35 bucks for 20*24 which is not cheap, but one of the better overall values IMO

Meysha · Nov 6, 2005

So you're saying there's no difference between an 800x600 image at 72 and one at 300dpi???

Marctwo · Nov 6, 2005

Yes, 800 pixels is 800 pixels! The dpi just tells the software how far appart the pixels are meant to be. You can change the dpi anytime and as often as you like without affecting quality (so long as you don't resample the image).

jstuedle · Nov 6, 2005

Yes, 800 pixels is 800 pixels! The dpi just tells the software how far appart the pixels are meant to be. You can change the dpi anytime and as often as you like without affecting quality (so long as you don't resample the image).

True, you have the same amount of data. But IF you re-shoot and have a good high quality image to start with, at normal viewing distance for a given size print there is no real limit to the size you enlarge your image. A 600 X 800 pixel image is too small and does not have enough data to make a good enlargement. If you can get a 4 X 6 out of it you will be fortunate. But if you had say a 5 MP file from a good DSLR, or 8 MP file from a small image chip camera big enlargements are very practical. I have made 36" X 54" enlargements from a 5.47 MP image that were stunning. A Google search for "big color prints" or something similar will return dozens of suitable labs. The whole trick is file preparation. If you have access to Photoshop set your DPI to 300 and up-sample the file size about 20% at a time until you reach your desired size. Do not save as a jpg at anytime through the upsizing process. Try to start with a RAW or TIFF file straight from the camera. If the lab wants the file in jpg, then only save as such at the very end of the process. Try to use a non-compression file format like TIFF or PSD as much as you can.

darich · Nov 6, 2005

jstuedle said:
If you have access to Photoshop set your DPI to 300 and up-sample the file size about 20% at a time until you reach your desired size

I've noticed someone else said a similar thing recently on this forum. Does it make a difference it you do, say, 3 enlargments to get to your required size rather than do it in one step?
What difference does it make?

Marctwo · Nov 6, 2005

One thing you could try is: Once you've enlarged the image to the required size, add a clumped grain effect in PS. This won't enhance the detail, of course, but it may help to make the poor quality look more natural.

Meysha · Nov 6, 2005

What I was trying to say is that if he resized all his photos and accidentally saved them as 72dpi and then he wants to print these... he's going to have to change the dpi to 300 and leave the size settings and come out with a tiny print, or change the height and width and massively increase the file size which in turn reduces the quality.

Marctwo · Nov 6, 2005

Well s/he didn't resize them to logical dimensions such as inches/mm, s/he resized them to actual dimensions in pixels so it really doesn't matter whether the dpi was 4, 72, 300 or 1200; The pixel dimensions are still the same.

As I said here, the image size dialogue box can cause a lot of confussion when it comes to resizing in PS.

jstuedle · Nov 6, 2005

I've noticed someone else said a similar thing recently on this forum. Does it make a difference it you do, say, 3 enlargments to get to your required size rather than do it in one step?
What difference does it make?

If you make the adjustment/enlargement in one big jump, especially if it is over a 50% jump, you will see a noticeable loss in image quality over making smaller jumps. PS up through version 7 would benefit with smaller increases in the 10 - 20% range. Version CS does a much better job and 20-40% jumps can be made. As a general rule, the smaller the jumps, the better the final image quality.

AIRIC · Nov 6, 2005

Where are you in Canada? Blacks Superstores have on-site poster printers. There is a location in Calgary and In Ontario at Ajax, Toronto, Woodbridge and Brampton. Let me know which store you talked to? If youa re close to one of these they should have told you about it.

Eric

DocFrankenstein · Nov 6, 2005

Meysha said:
So you're saying there's no difference between an 800x600 image at 72 and one at 300dpi???

Yeah... all of the labs ignore the file's dpi settings anyways and prints to the size you specified... be it 20*24 or 4*6

DLL_4ever · Nov 6, 2005

jstuedle said:
Try to start with a RAW or TIFF file straight from the camera.

I don't think i can. Or if i can, i have no idea how. I have a Panasonic Lumix DMC-LZ2 and theres no option anywhere that allows me to change the pictures from JPEG to RAW or TIFF.

AIRIC said:
Where are you in Canada? Blacks Superstores have on-site poster printers. There is a location in Calgary and In Ontario at Ajax, Toronto, Woodbridge and Brampton. Let me know which store you talked to? If youa re close to one of these they should have told you about it.

Eric

Well i used to live in Ajax. But now i live in Lindsay, ON. There's a Blacks Superstore here too and the woman i talked to said they only offer photo prints of up to 10x8.