As many film photographer will know, getting sharp scans out of a flatbed scanner is challenging at best, especially if you're doing it at high resolution, for example for inkjet prints. The issue lies mostly in the scanner's optics: most flatbeds with TMAs have a fixed focus lens that is rarely tuned to precision, and while the sensor and stepper motors could be capable of acquiring high resolution (altough noisy) images, if the media is out of focus or the lens just isn't that sharp, the actual, optical resolution of the captured image will be much lower, often in the 1400 to 2000 DPI range.
While 120 film, with its larger area, is more forgiving to lower resolution scanners, you might give up on getting a sharp scan out of a tiny 135 frame on a mid-range flatbed. However, they can be made to work for up to 13x18 prints (and maybe 18x24 if you're not too hung up on details), and they are certainly suitable for social media uploads. The key is to find a proper workflow, as often the software provided by the manufacturer is uncapable of delivering neither a high color depth for later grading in photo finishing software, nor a satisfying native inversion.
I've
developed the following workflow for my HP Scanjet G4010 and G3010
scanners, which have an optical resolution of about 1400 DPI. It works by capturing a positive image and then inverting it manually in RawTherapee.
1. Capture a positive, 48-bit TIFF file from VueScan or Silverfast
This is crucial in order to retain the full color depth, and having maximum flexibility when inverting and grading the negative. My VueScan settings are as follows.
Input:
- Scan resolution: as high as it goes. My G3010 does 4800 DPI, so that's what I will select. If you're running low on disk space you could go lower, albeit losing a bit of editing flexibility, and not really notice a difference. On my setup I could go as low as 2400 DPI without losing significant detail
- Mode: Transparency (it lights up the TMA lamp and scans only the negative strip area)
- Media: Image (it captures the negative without doing any inversion)
- Bits per pixel: 48-bit
- Lock exposure (ensures all negatives are scanned to the same exposure settings)
- Mirror (you should load the negatives emulsion-side down, and this flag ensures the output image is already mirrored)
Crop:
- Crop size: Maximum, Multi crop: Off (it seems that the frame detection does not work great when dealing with negatives)
Color:
- Color balance: None
- Output color space: Adobe RGB (again, we want to retain the most information in our TIFF file)
2. Inverting it in RawTherapee
RawTherapee has a built-in Film Negative profile. That will, however, require adjustments in:
- The reference exponent (tuned to the lightness of the negative)
- CMY levels
- White balance (in order to balance a scanner light that could be slightly off the 5500K mark)
Tune those values to a baseline that is identical and looks good across all the scanned negatives. That means:
- No cyan, magenta or yellow "casts" on the pictures
- White balances of the scan matches the white balance of the film stock
- No burnt highlights, no muddy shadows
Then apply the profile to all the negatives in the batch, and you can start grading then one by one.
3. Some tricks to make a low resolution, noisy scan look good
You cannot recreate detail that was lost to the scanner's poor optical performance. What you can do in order to mitigate a soft looking image, is to use an unsharp mask and local contrast enhancement to fake it into looking a bit more sharp.
Also, those scanners produce pretty noisy output. The Noise reduction tool in RawTherapee, when set to work in the L*a*b* color space and in Conservative mode does a good job of removing a bit of RGB noise without further destroying the sharpness of the picture.
As a side note, some insist that you should not grade your negatives digitally, as it detracts from the film stock's characteristics and color science. I think that's nonsense, since even when doing darkroom prints you're expected to be doing some fine tuning in terms of filtering and exposure, but you do you.
The obvious drawback to this method: it takes time. Certainly, if you're in a hurry, VueScan or Silverfast might do an okay job of inverting negatives, and if you save them to 48-bit TIFF you still retain huge flexibility for doing later edits. What you will lose by letting the software doing the inversion for you is the consistency of having every frame inverted to the same exact baseline spec.
To conclude, a wholehearted recommendation: if you're serious about shooting and scanning film, get a dedicated film scanner (Primefilm or Plustek scanners are good, cost-effective options) or a DSLR scanning setup. But if you're dipping your toes in this your old scanner might work fine for Instagram posts, and there's a lot that can be squeezed from even an older, cheaper machine.