DPI?

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Framar

Framar

WOW Framer
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Buffalo, New York, USA/Fort Erie, Ontario, Canada
Back when my late partner Kim made the switch from traditional photo retouching to Photoshop, she determined that scanning photos 8x10 and smaller for prints 8x10 and smaller turned out best if scanned at 300DPI and saved in a TIFF format. This worked well. The resulting images were less than 20MB and printed out just fine.

Then along comes the big photo fixing place who ask that an 8x10 photo be scanned at 300DPI and saved in a JPG format for a finished 8x10 print. I have't tried their services yet but I am skeptical of the possible quality in a JPG file size.

Then along comes my new Photoshop guy, who is also my computer whiz kid fixer of all things computer, knower of all things techy. I give him an 8x10, a 20 year old black and white portrait that had fixer stains on it and the lady was also in need of a "bit of work" on eye bags and crows feet.

He scanned it as a 1200DPI TIFF, it ended up being almost 300MB, I couldn't even open it on my good computer - and my printer guy, who is a pro who had been doing photography stuff for the last 30 years and has both Mac and PCs of the latest and greatest variety - well he said it crashed his computer 3 times when he was trying to open it to print it.

The print turned out lovely.

But surely there is a happy medium between a 300DPI JPG and a 1200DPI TIFF?

I tried to have a bit of a conversation with the techy guy and his stand on file sizes is "You can always make them smaller but you cannot make them bigger."

Any suggestions?

I like having this guy as a back up locally - his work is great, he is a good friend - but he is a GUY.

How big does an 8x10 print have to be to be really good???
 
The general rule of thumb for photography is that a print at 300 dpi, or ppi (pixels per inch) will be sharp for a viewer at a normal distance. You can scan it at higher resolution if you want to do serious editing.

However, a lot of film images just aren't that sharp or good quality. If so, going overboard will just give you higher resolution dust and grain.

While your computer guy is right that you can always downsize the image, but not generate more data, it's not very useful if you can't open the file. If you want to do major edits to a photo, it makes sense to save it in TIFF, since you're not losing any data. However, if you scan to photoshop, and do the corrections, then saving to a high quality jpeg is fine. I would suggest setting the quality to 8-12 in photoshop (80-100%) in other programs.
 
Another thing to keep in mind is the printer that you will use to print the image. Even is you scan the image a 1200dpi, if the capabilities of your printer is only, for arguments sake, 300dpi, it will only print at the lower dpi.

Regards,
Troy
 
I have worked with two guys who have scanned at really high resolutions and then all I hear is how much work they had to do with spotting and such. I did try to make a correlation to high res/lots of spots but neither guy gets it.
 
Scanning at 1200 is usually only needed if you are going to make the final print larger than the original. If you are still going to print at 8x10 then, as it will print at 300 dpi, you only need to scan it at 300 dpi.

I can see scanning at maybe 600 if you want more pixels to play with in correction mode. Then when you are done, you reset it to 300 and send it to the printer.

I open 300Mb files all the time with no problems.

If it is crashing a computer, odds are the memory for Photoshop needs to be bigger or even the computer needs more RAM.

Unless the computer is old and has limited RAM, a file this size shouldn't be a problem... especially for your "printer guy a pro". Something is wrong here.

As for TIFF vs JPEG, yes everything is better off being saved as a TIFF as you will not lose information each time you open it like you do with a JPEG.
 
I prefer to save the "original" as a TIFF, but save a JPEG for printing at Photoshop's highest setting - prints much faster because it is a considerably smaller file. I have printed the same image both ways, and I can't detect which is which.
 
TopHat said:
I have printed the same image both ways, and I can't detect which is which.
Click to expand...

Very interesting.

I am so gonna pass that along to my techno nut.

Thanks!
 
My experience has been that 300dpi is the happy medium. The image quality is more than acceptable and the file sizes aren't too big. As others have said, you only really need more if you're going to be significantly enlarging the image (I scan 35mm slides at 4800dpi, f'rinstance).

Although modern printers claim to print ridiculous numbers of "dpi", realize that this is *ink* drops per inch. The printer driver has to dither together a number of ink drops of various colors to render a pixel. If you feed an image to the printer at its "native" dpi (e.g. 1440) it's *still* going to downsample the image so it can dither it properly.

In my experience, with my equipment I have found that I can often get acceptable print quality at resolutions as low as 100dpi (as I said, it's all in the rendering in the printer driver).

I prefer to do all my work as much as possible in a lossless format, such as TIFF or PSD. To me JPG is only suitable for final output and for web images. Every time you work on a JPG and save it, you lose a little resolution and a puppy dies :)

I once had a customer who gave me two images to print; the first was the original JPG and the second was one that he had made some corrections to. The second was jam-packed with visible JPG artifacts. Turns out he alternated between two different programs to work on it, and saved it as a JPG each time. I had to explain to him why this was a Bad Idea...
 
I forgot to mention that I print at 400 dpi - not sure if that makes a difference or not. Next time I have a smaller print, I try a 400 dpi and a 300 dpi and see if I notice any difference.
 
Digital Custom recommends scanning at 300 dpi unless you have a tiny original and want a large print, in which case they say 600 dpi. I never scan above 600 dpi for the reasons mentioned above.
:cool: Rick
 
Lots of variables. I've found 300 DPI to be more than adequate as long as I'm not blowing the image up. I generally scan at 600 DPI but find that for the general case it doesn't add quality to the prints (again without enlarging); it just slows down the printer and uses more ink.

A major variable is the printer's native resolution. Even for printers that print 2800x1400 (as does our Epson SP 7900), the native resolution is much lower than that & the driver handles mapping to the DPI you tell it to print at.

In practice, I only use higher DPI when enlarging. So if I need to print an 8x10 as 16x20, I'll use 600 DPI.

Another variable is the image itself. For images that are soft & lacking in detail, higher resolutions won't make much difference. You can often get away with printing fairly large prints at lower resolutions, depending on the actual sharpness and detail level of the original.

I only scanned once at 1200 DPI, and it was per customer request. File ended up too big for a CD so had to go on a DVD. 800+ Mb as I recall. It did stress out Photoshop to view it, but it worked. I have no idea what they needed that resolution for, but I got paid & didn't ask.
 
If I am printing the image the same size I scan at 300 DPI. If the customer requests it to be scanned higher then I would do it and also charge more for that since it will take longer to scane and take up more space.

I remember a number of years ago that a tech rep for a printer company had said that printers will scale down the file to 150 dpi when it get the file. I dont know if this is true to todays printers.
 
I'm an artist and have been fortunate that a Cruse scanner is available to me nearby. I'd venture to say it sets the bar for scanning in most respects. It scans at 300 DPI I believe but it scans direct from an original painting. File size can be as high as 450 MB although I doubt many will approach that size. 100 MB+ files are not unusual however.

It does an amazing job with the right technician major amounts of RAM and processing power for PhotoShop.

http://www.crusedigital.com/cd_main.asp
 
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