I’ve talked before about scanning resolution for photo restoration but I still can’t believe what I am seeing out there on the web.
Photo restoration isn’t an exact science but it can only be achieved if the original image is created as a digital file. This file must be of a certain size for the restoration to be made. Digital images are made up of pixels, single points of light and colour in varying intensities. If there are not enough of them the photo restoration cannot be made.
To create a file with enough data photos are usually scanned into a computer. So many restoration websites ask customers to scan their photos at 300 dpi. This means there will be 300 of those tiny pixels per inch. What if that photo was only an inch square? Then it would only have 300 pixels by 300 to restore with. You would probably want that image enlarging, wouldn’t you? Alas, it wouldn’t be possible with a scanning resolution of 300 DPI, I’ll explain.
To an ordinary person who knows nothing about the digital world this may sound like techno-speak but what it means is that your image is effectively like a Roman mosaic. If there is a crack through the images and it has a stain or tear, trying to restore this would be impossible. There are simply not enough mosaic tiles to move around to fill in and patch up the photo.
If the number of pixels increased for this little 1-inch photo to say 2400 DPI or 2400 pixels along the edge of the photo this would mean not only would be millions of little squares to restore but it also could be printed in a variety of sizes.
Requesting a scan for a photo restoration from a customer without even asking what they require in terms of restoration size is extremely presumptuous. You simply cannot set this scanning figure in stone as so many of the photo restoration services do. It’s very much like building a house without first working out how many people are going to be living in it. You wouldn’t build a 2-bedroom terraced house for a family of 12, would you?
300DPI scanning resolution would be fine for large images such as those of 7×5 inches or above but again it cannot be assumed the final image is to be the same size when restored. I’ve found that most people want their old images enlarged so they can see more or display them with pride.
Can you lighten the pictures I’ve scanned at 300 dpi?? We haven’t even talked about grain and shadow detail either. If said small image was canned at 300dpi and the request was to “lighten” and “enhance” the detail the image would end up looking like a bunch of pebbles on a beach. The more pixels you have in the scan will enable the shadow areas to be probed and lightened, to squeeze as much shadow detail out as possible without those little pixels showing through as noise or grain.
To summarize, requesting a scan of 300DPI for a 1-inch image means it can be printed at one inch, what if you wanted it 10 inches square? The correct question to ask a customer would be “Tell us what size you would like the photo to be and will tell you what setting to scan it at”. Assumptions in photo restoration will get you nowhere, just into hot water when it comes to providing what the customer wants. Always ask and advise, don’t assume when it comes to photo restoration. For more on this topic visit saving your file correctly for photo restoration.