If you’re into posting photos on websites like Instagram or Facebook, but want to get more into film, you’ll probably want to invest in a photo scanner. That way your online following can see your film stuff too! Or let’s say you have a lot of photos on film already, and want to not only upload them online but also preserve them for future generations. In this case you’ll also want a scanner.
Finally, if you want to make enlargements of your photos, or if you want to crop them and then print them out in various sizes…you’re going to need a scanner.
Here we’ll go into some of the basics about high resolution photo scanners, and we’ll talk about how the whole process works. In the beginning, there were pixels. (Well, not really. Actually, in the beginning were tintypes and shadow cameras and camera obscuras and all sorts of things, but when it comes to understanding digital images, it all starts with the pixel.)
Every digital photo is composed of many teeny tiny picture elements, sometimes called ‘dots’ or squares even though depending on the camera their size and shape can vary. Either way, pixels are tiny pieces of a photo, and even small photos these days contains millions of pixels.
That’s actually where the word ‘megapixel’ comes from; one megapixel equals 1 million pixels. Each one of these pixels is made up of three ‘pieces’ of the color spectrum; red, green, and blue. Let’s take a 24-bit color image for example; it would have 8bits of red ‘info,’ 8bits of blue information, and 8bits of green. This can be thought of as a kind of ‘color code.’ This color code has 256 possibilities; 0 to 255.
Colors are made with pixels by mixing the numerical values of the three base colors, just like how paint is made through physically mixing it up in a hardware store or something. For example to make green, you would aim to have a high green value with very low or no values in the other color columns. To make a color like purple, you mix red and blue.
Once all the ‘dots’ are proportioned correctly to create colors, all the pixels are laid out in a grid to create the image. A TIFF or a GIF or a JPEG file, then, contains the grid coordinates and color number values for all the millions of pixels in the photo.
We’ve all seen this if you zoom in tight enough on a photo in Microsoft Paint or in Photoshop at some point things start to look grainy or unclear. This is because you’re actually seeing the pixels! This is why megapixel count of an image matters somewhat; the larger the pixel count, the more you can zoom in and crop the photo without it looking crappy. Of course, the human eye has its limits like any other sense of the human body.
It’s strange to say it, but we have actually surpassed the quality of human eyes with digital pictures. This is why scanning photos at super high resolution doesn’t make a lot of sense if you’re just going to upload it to Facebook; computer screens, phones, and our eyes won’t be able to discern the image as any richer than about 300dpi.
What is DPI? Why is DPI important?
So what’s DPI? Dots per inch! This of course is the amount of dots in the area of the photo covered by an inch of ‘real estate’ on the print. You might also see this written as PPI (pixels per inch) or SPI (samples per inch.) They all basically mean the same thing, which is that a printer will reproduce x amount of dots in that space, or a scanner will pick up and read that same amount of dots.
How this creates ‘resolution’ is this; if you scan a 5inch by 7inch photo at 300dpi, you’ll have as a file inside the scanner that is 1500 pixels by 2100 pixels. This is because 5×300 = 1500, and 7×300 = 2100. This is how to understand and visualize the concept of resolution; larger numbers equals more dots.
The real question is how high should your resolution be before it stops mattering at all, or even starts to be a negative? Most pictures have around 300dpi of information in them, some even less. Prints usually stop around 600dpi. What need to be scanned at super high resolution are film negatives and photographic slides. Both of those formats include a high amount of detail.
Depending on film type and the speed at which the film was shot, there may be a whole lot of detail involved. Plus, these are what people call ‘archival formats’ for professionals. If you intend to scan these types of items, you will need a high-resolution scanner and some decent storage space. Luckily, these days even 1 or 2 terabyte storage is relatively inexpensive.
Film Resolution Recommendations
OK, so now you’ve realized you have high-quality media that you want to save forever. Whether we’re talking older photographic products like daguerreotypes or tintypes, or newer things like negatives here’s the info you need. If you plan to make prints of your film or slides, here are some recommendations.
At 2000dpi, you can get really nice 3×5, 4×6, and 5×7 prints. For 8×10 or 11×14 prints, we recommend going up to 4000dpi if possible. You could probably get a decent 8×10 at 3000dpi however.
For 16×20 prints, go up to 5000dpi if not higher. For 20×30 prints, go up to 6000dpi. Of course, it is definitely possible to make prints with scans that aren’t as detailed as 2000-5000dpi, but they will of course not be as detailed as the originals.
Another final tip is to try and use .TIFF file format if you want to have the highest quality possible. Yes, .TIFF is sort of dying as a format, but for pro uses it’s still the best. JPEG/JPG is decent, but it’s lossy.
Hope these tips help you understand High Resolution Photo Scanners and how they work!