Slide copying & processing

[ms.fuentecilla]

I am busy digitising a large slide archive by scanning. The scans are saved at 4800dpi. Normal digital images at that resolution will resize with little if any visible deterioration. However, if I attempt to downsize a scan it pixelates into a total mess. The images are JPEGs. Apart from rescanning at a lower resolution is there a way using AP to avoid pixelation to this extent? Does anybody out there have experience of this please?

[John Rostron]

I take that the second image is as originally scanned. How did you resize the first  image? What width and height did you specify? What dpi? Did you resample? What resizing algorithm?

Your pic looks like it was taken in the Isles of Scilly, possibly St Agnes.

John

[ms.fuentecilla]

Hello john

It was indeed St Agnes, one of hundreds from the islands. And yes, the second image is the original scan. Since uploading this I have realised that I shouldn't specify a new dpi, which I did at 400 but specify an actual pixel count. Is that what you would say? I have also learned to use the scan software much better, (These were among the first.) together with post processing in Affinity Photo. To begin with I scanned to TIF but there was no perceptual improvement over quality JPEGS.

Sadly the original transparencies have to be disposed of (that hurts!) because my daughter (also a photographer) has no space to inherit them, so I am attempting a digital archive for her of which these are a small but very important  part.

Thank you for your reply.

Michael

Edited March 4, 2022 by ms.fuentecilla
clarity

[John Rostron]

Yes, it is the pixel count that matters. The dpi only becomes important when printing. What algorithm did you use when rescaling the image? The Lanczos methods are usually best for photographs. 

I also have many hundreds of images (now mostly scanned)  from the Isles of Scilly. We ended our holidays there when we got too infirm for the rough paths!

John