Scanning period LW photos for digital archive

[Flying_pencil]

Some advice from the wise members here.

I am working on scanning in the photos I have collected over the years.
While I have scanned a portion, I want to make sure I am using best practices.


I use 2400 DPI scanners and scan to the maximum.
Afterward I re-sample down to 1200 DPI, as this produces more accurate 1200 DPI images instead of doing it 1200 (as the source has a finer details so the interpolation, the average area result, is more accurate, IIRC).
This is to save space and work times (big files, long action times).

I also save as PNG
JPEG is a "lossy" format, throws data away to reduce file size. Great for web, email, publishing, not good for archive of original.

I tried TIFF, but there is actually no standard, so certain file information is not understood or used by programs, causing problems.
I even use GIF in grey scale, it will have 256 shades of grey that make for great images and very small files (but on closeup the 256 pixelation does show a bit).

Easy comparison of files here (http://www.scantips.com/basics09.html)

How Photoshop advises on re-sizing (scroll down 1/4 way) (https://helpx.adobe.com/photoshop/kb/advanced-cropping-resizing-resampling-photoshop.html)
see:


Changing the pixel dimensions affects the physical size but not the resolution.
Changing the resolution affects the pixel dimensions but not the physical size.
Changing the physical size affects the pixel dimensions but not the resolution.



What do you do any why?

[Richard T. Eger]

Dear "Flying Pencil" (a real name would be better),

I typically save my scans to .tif. My professional photographer friend likes to work in Adobe's .psd. However, for quick viewing, .psd's don't open in my version of Microsoft's viewing software, so I am forced to look at his .psd's in Photoshop, an inconvenience when doing a photo search. Not being fully conversant with the options each provide, I'm guessing that the .psd's give him more latitude in photo enhancement.

As you seem to have realized, the image zoom-in detail can't be upgraded after you've saved it. So, if you save to 600 dpi and later want to zoom in to some spot on the photo, you won't get as much detail as you would if you'd scanned at 1200 dpi.

Of course, you have to take into account just how good your original is to start with. If it is an out of focus or very grainy WW II G.I. shot, scanning at 1200 dpi isn't likely going to help.

You also need to consider what your intended printed end product might be. For me, this is an 8" x 10" print. So, if I am starting with a 2" x 3" snapshot, I scan it in such a way as the output gives me roughly an 8" x 10" image at 600 dpi. Some snapshots are remarkably sharp, so you can do this. Others, not so.

Also, when scanning, your photo may have a particular area of interest, say aircraft around a hangar in an aerial photo. So, besides capturing the photo as a whole, you may want to go back and zero in on the hangar and the area around it, again planning for an 8" x 10" print of this area.

The limitation of digital images is that you lose the ability to keep zooming in as you have with an analog photo. Thus, the above advice.

One positive in scanning an analog photo over just having the photo is that there is detail in the photo that the naked eye can't see. For instance, the underside of the aircraft may be in very dark shadow and the sun struck side of the fuselage may appear to be a white-out blizzard. Enhancing the scan of the photo can frequently bring out the details hidden in these areas. Enhancing a photo is an art. Too much and it looks unreal and Photoshopped.

Regards,
Richard

[Flying_pencil]

You also need to consider what your intended printed end product might be. For me, this is an 8" x 10" print. So, if I am starting with a 2" x 3" snapshot, I scan it in such a way as the output gives me roughly an 8" x 10" image at 600 dpi. Some snapshots are remarkably sharp, so you can do this. Others, not so.

Also, when scanning, your photo may have a particular area of interest, say aircraft around a hangar in an aerial photo. So, besides capturing the photo as a whole, you may want to go back and zero in on the hangar and the area around it, again planning for an 8" x 10" print of this area.

The limitation of digital images is that you lose the ability to keep zooming in as you have with an analog photo. Thus, the above advice.

One positive in scanning an analog photo over just having the photo is that there is detail in the photo that the naked eye can't see. For instance, the underside of the aircraft may be in very dark shadow and the sun struck side of the fuselage may appear to be a white-out blizzard. Enhancing the scan of the photo can frequently bring out the details hidden in these areas. Enhancing a photo is an art. Too much and it looks unreal and Photoshopped.


That is some good advice concerning size of original, and have some selective high DPI scans on interesting areas.
Get the detail without overloading the drive.

Why you prefer TIFF over PNG?

Thanks

[Richard T. Eger]

Dear "Flying Pencil",

I don't use .png, so I asked a professional photographer friend of mine what he thought of it versus .tif. Here's his reply:

"Richard,

I don't use that format either, so I looked it up. According to what I read, it's tif for sure. Png was designed for transferring images on the Internet.

Jim

Portable Network Graphics (PNG /ˈpɪŋ/[2][3]) is a raster graphics file format that supports lossless data compression. PNG was created as an improved, non-patented replacement for Graphics Interchange Format (GIF), and is the most used lossless image compression format on the Internet.[4]

PNG supports palette-based images (with palettes of 24-bit RGB or 32-bit RGBA colors), grayscale images (with or without alpha channel), and full-color non-palette-based RGB[A] images (with or without alpha channel). PNG was designed for transferring images on the Internet, not for professional-quality print graphics, and therefore does not support non-RGB color spaces such as CMYK."

You are likely sticking with RGB, so perhaps it makes no difference to you. However, I think that .tif is the general standard used for lossless image saving. Jim, by the way, converts my .tif images to Adobe's .psd for his enhancement work. Once in a great while, I'll ask him to try converting the images to RAW to see if we can adjust the density of an either under exposed or over exposed original. Once this is done, he'll switch back to .psd. The .psd has the ability to save the individual layers Jim uses in his enhancement work. This can be eliminated, if desired, by flattening the image. In Adobe, he or I can re-save the image as a .tif, as this makes viewing easier for me. And, if I want to share with a friend via e-mail and yet share as a high resolution image, I'll convert the image to a .jpg at the least compression setting.

There are other ways to share a large image via the Internet, such as WeTransfer or Dropbox. I don't get into motion pictures, so DSL is adequate for my needs. My ISP limits my inbox to about 30 MB's and other ISP's may have similar limitations, so use of WeTransfer can get around this problem.

Regards,
Richard