Working out best scan resolution

[ahelg]

I've just scanned four old slides. I'm quite pleased with the result, but seeing as these slides are relatively old, probably mid 70's, there is a lot of grain in them. When I scan I scan at max resoltuion which gives me about 100 mb pictures. This is a lot concidering that there is loads of grain viewable. So I was wondering if there is a program out there which I can run my photographs through which will check grain size and chose a suitable resultion for the photograph.

 

[Don Simon]

100mb certainly is a lot; are the slides medium format? If so then it would make more sense than if they were 35mm. Also what scanner are you using?

Anyway I don't know of any such programs, but IMO your own judgement is best. A lot of people scan at 1600. I scanned at 1600 for archiving the family's old slides, but with my own negatives I scan at 3200, do any PS work and then resize as necessary. Have a go scanning at different resolutions and see which you feel is best.

 

[Philip Weir]

I've just scanned four old slides. I'm quite pleased with the result, but seeing as these slides are relatively old, probably mid 70's, there is a lot of grain in them. When I scan I scan at max resoltuion which gives me about 100 mb pictures. This is a lot concidering that there is loads of grain viewable. So I was wondering if there is a program out there which I can run my photographs through which will check grain size and chose a suitable resultion for the photograph.

Hi, I might suggest that just because the slides are old, there is a lot of grain in them is a misconception. Sure modern film films have improved immensely as far as grain is concerned, but I have many old glass negatives that are super fine, and probably 100 years old.

You need to decide what size your final result needs to be, then scan for that size at say 300 dpi. You can only check the grain size by scanning and blowing up on your monitor. 100mg files are huge and unless you were doing a poster for the side of a bus, you wouldn't see any advantage in scanning to that size.

www.philipweirphotography.com

 

[ahelg]

They were scanned at full res before I made them smaller and I could see all the grain when I viewed the file at 100% in photoshop. It was all over the place. I scaled them down and they are now at an avarage of about 35 - 45 mb each depending on dimensions of them. Some of them are in the same format as today but they are mostly square shaped where the bottom is just as long as the sides.

 

[markc]

What resolution did you scan at? Was it only using optical or did you have software boost it? When I scanned, I used the maximum optical resolution my film scanner (35mm) would do, and 2700 dpi resulted in (I think) a file around 27MB.

 

[ahelg]

I used max on the scanner I used, but it has a much higher dpi. 4800 I think it was.

 

[markc]

I'd just make sure that all of that is optical resolution and not interpreted. Some scanner software will allow you to boost resolution artificially. If you can deal with the file size, I'd stick with 4800 optical for most things, but if you are getting a lot of grain, you could turn it down some. I don't think there is anything out there that will tell you what res to use, so you will probably have to experiment.