colyn
ישו משיח
I have quiet a few color negatives that I want to get scanned. Too many to do myself so I will be getting them scanned elsewhere.
I have a chance to get some printed at work for free and was wondering what resolution I should have them scanned to in order to print to 20x30 inch sizes.
We use chemical processed Kodak Endura papers instead of inkjet..
I have a chance to get some printed at work for free and was wondering what resolution I should have them scanned to in order to print to 20x30 inch sizes.
We use chemical processed Kodak Endura papers instead of inkjet..
tlitody
Well-known
Ask the people where you will get them printed what ppi figure they use to print and then you can work out what is required for the scan.
colyn
ישו משיח
We get all sizes. Most will print ok at enlargements up to 8x12 but if you want larger sizes they will print even though the images start to lose quality (whatever the customer wants...). I plan to enlarge to 20x30 so the drug store and retail store scans won't work.
I have enlarged images from my D90 and D200 which are both set to capture maximum size.
DNG
Film Friendly
Simple Answer
If you are not getting anything bigger than 8x10....
Use 300dpi use this formula (250x8)+(300x10)=resolution of 2400x3000, or a 7.25mp file
some places offer 2400x3600 scans)
If you want larger. Multiply each dimension by 300 and then multiply the 2 answers together for the MP file size. (as above example)
If you are not getting anything bigger than 8x10....
Use 300dpi use this formula (250x8)+(300x10)=resolution of 2400x3000, or a 7.25mp file
some places offer 2400x3600 scans)
If you want larger. Multiply each dimension by 300 and then multiply the 2 answers together for the MP file size. (as above example)
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Bob Michaels
nobody special
I agree with above, except the method of computing the 7.25Mb file size. Besides number of pixels, file size is determined by:
1) 8 bit or 16 bit file
2) RGB or Greyscale file
3) file type (TIF, PSD, JPG)
I am sure there is some combination of 1, 2 & 3 that the 2X factor yielding 7.25 Mb file size works. But I can make a 2400x3000 pixel file come out to just over 1Mb without using any compression (i.e. 8 bit greyscale TIF)
colyn
ישו משיח
I might also add that we only accept 8 bit sRGB files b&w or color.
Klyment
Member
If the pics are worth scanning they are worth scanning well. The human effort required to scan to 8bit or 16bit per channel, TIFF, JPEG, or whatever is the same and depending on resolution and bit depth, scan time doesn't vary significantly. If you can get the 16bit per channel files you can always batch process them back down to conform with your lab's acceptable file formats and still have an archive of the film that you can easily re-purpose in the future.
tlitody
Well-known
some labs print bigger images at lower ppi because, I think, the viewing distance is normally further so they don't need 300ppi output to give apparent detail. So any formula should or should not include that depending on what the lab do. So once again, the output ppi dictates what you have to scan it at to get the right size file.
Chriscrawfordphoto
Real Men Shoot Film.
A 35mm neg is really too small to get a good print that big. If you insist, get it scanned on a drum scanner or by someone with an Imacon or a Nikon 8000 or 9000 with the glass carrier to get the neg absolutely flat so every detail resolves.
colyn
ישו משיח
This is what I want to do...have someone besides drug/retail stores do it right so I can get prints at that size. These scans are maybe good enough for 8x12 inch enlargements but I plan to go as high as 20x30 inch so I need to know what size scans to have done.
It can be done since we have a couple of customers who still work with 35mm and have their negatives digitized before sending the files to us and printed by to those larger sizes.
tlitody
Well-known
Ok at a minimum you will need 200ppi output. So 30x200 = 6000 and 6000/1.34 = approx 4500 spi but if you want 300ppi output then you would need to scan at 30x300 = 9000 and 9000 / 1.34 = approx 6800 spi.
If you are a lab then you should know this stuff. 200ppi output would probably be good enough unless you are a print sniffer.
Best quality output uses 400ppi to a lambda but the difference between 200ppi and 400ppi is small and maybe not even noticeable especially at normal viewing distance for a 30x20 print. Depends on the quality of the file to be printed. i.e. how good the scan was and the processing you have made on the file. Some look awful and others are good.
And when you are scanning at 4500 or 6800 your neg/pos better be of the very highest quality to start with otherwise you'll get crap.
The oldest wisdom in computing tells you that if you put garbage in, then you get garbage out.
If you are a lab then you should know this stuff. 200ppi output would probably be good enough unless you are a print sniffer.
Best quality output uses 400ppi to a lambda but the difference between 200ppi and 400ppi is small and maybe not even noticeable especially at normal viewing distance for a 30x20 print. Depends on the quality of the file to be printed. i.e. how good the scan was and the processing you have made on the file. Some look awful and others are good.
And when you are scanning at 4500 or 6800 your neg/pos better be of the very highest quality to start with otherwise you'll get crap.
The oldest wisdom in computing tells you that if you put garbage in, then you get garbage out.
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htimsdj
Established
What is your "1.34" used for?
To get a 200 dpi 20x30 inch print from a 35mm film frame, you will need a file of 4000 x 6000 pixels. This is scanning at 4000 dpi.
To get a 200 dpi 20x30 inch print from a 35mm film frame, you will need a file of 4000 x 6000 pixels. This is scanning at 4000 dpi.
tlitody
Well-known
36mm = 1.417 inches. I used 34mm because unless you are printing absolutely full frame you are going to lose something. But at 1.417 inches then 1.417 x 4000 = 5668. I won't be entrusting my scanning to you.
htimsdj
Established
I guess that would be for two reasons: (1) I cannot read your mind about your factor and (2) my scanner only goes up to 4000 dpi. 
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dmr
Registered Abuser
OMG, 20x30! Are you really sure you want to do that?
The largest I've done is 13 x 19 and that does show some grain, and accentuates imperfections.
For those, I've scanned at max resolution (3200 on the SD IV) 16 bit, which comes out to a file of something like 60-70mb per frame! I've done a few stunning prints at that size, but there are a few I did not print that large after closely inspecting them in Photoshop.
The largest I've done is 13 x 19 and that does show some grain, and accentuates imperfections.
For those, I've scanned at max resolution (3200 on the SD IV) 16 bit, which comes out to a file of something like 60-70mb per frame! I've done a few stunning prints at that size, but there are a few I did not print that large after closely inspecting them in Photoshop.
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ColSebastianMoran
( IRL Richard Karash )
Colyn, starting from 35mm and wanting a large print, here's what I would do.
1. You are not going to get a scan with enough pixels for the image size you want, so get the best scan you can. I scan 35mm on a Coolscan at 4000dpi. 16 bit scan, if you can. Or get an 8bit scan from Precision or NorthCoast.
2. Noise reduction. I find it a must with scanned film.
3. Image adjustment... The usual. Brightness, contrast, dodge/burn, crop, etc.
4. Up-Res with Genuine Fractals (now Perfect Resize) or Photoshop or another program specific to this purpose. Create an 8bit sRGB file at 300ppi for the size you want to print (or whatever ppi your printer wants).
5. Sharpen for print on the paper you will use. Lightroom has good defaults. Or read Bruce Fraser Real World Sharpening for Photoshop CS2.
I like my prints, even big ones, with enough detail and sharpness to stand up to close inspection. Without step 4, I get good results from carefully shot 35mm at 12x18 which is about the output resolution of my 4000dpi scans. Haven't tried larger.
Good luck. Let us know how this turns out.
1. You are not going to get a scan with enough pixels for the image size you want, so get the best scan you can. I scan 35mm on a Coolscan at 4000dpi. 16 bit scan, if you can. Or get an 8bit scan from Precision or NorthCoast.
2. Noise reduction. I find it a must with scanned film.
3. Image adjustment... The usual. Brightness, contrast, dodge/burn, crop, etc.
4. Up-Res with Genuine Fractals (now Perfect Resize) or Photoshop or another program specific to this purpose. Create an 8bit sRGB file at 300ppi for the size you want to print (or whatever ppi your printer wants).
5. Sharpen for print on the paper you will use. Lightroom has good defaults. Or read Bruce Fraser Real World Sharpening for Photoshop CS2.
I like my prints, even big ones, with enough detail and sharpness to stand up to close inspection. Without step 4, I get good results from carefully shot 35mm at 12x18 which is about the output resolution of my 4000dpi scans. Haven't tried larger.
Good luck. Let us know how this turns out.
colyn
ישו משיח
We don't scan. Images we print come to us already scanned or are files from a digital camera.
colyn
ישו משיח
This is the answer I was looking for.
I am wandering though my 12 MP D90 gives me a average file size of 4288x2848 +/_ which easily prints to 20x30 inch so why would a scan of a 35mm neg have to be larger?
colyn
ישו משיח
OMG, 20x30! Are you really sure you want to do that?
Only a select few would be printed that large. Others would be printed smaller.
Many of my digital images are printed to 20x30. These are the ones that get the most compliments from friends and visitors.
My favorite sizes are 16x20 and 16x24.
colyn
ישו משיח
I would have to respectfully disagree here since we have customers who scan (or get them scanned) 35mm negs and upload the digitized file for us to print to this size and larger with outstanding quality.
I no longer scan myself and want to find a good service that will scan my select negatives. Drug/retails store scans are worthless for anything larger than 8x10 max so they won;t do..