Bits and pixels

Do you ever wonder about bit depth and the pixel count? May be there are other things to worry about which are more important  – however this is what I am thinking about right now! (The SpaceX flight has been put back till tomorrow and I am still sitting downstairs with my computer). I suppose the reason this is in my mind is because of two projects I was working on earlier. One was an interesting motor vehicle project on 35mm slides and I was able to enlarge the images dramatically. The other was a black and white 35mm negative film which I have been having to restore. In both cases I have been concious of the colour and resolution and I thought it would be good to write a note about them for the website blog even though I have covered this before. I have added links to Wiki for this article so that the reader can get a more in depth account if she or he wishes.

At Saturn Films 1969 we have always gone for the most appropriate bit depth for the technology we are using, currently we use 24bit imaging. This gives us a very good colour palette of 16,777,216 colours. This is the current optimum and the images we produce are very true to the original. Wikipedia have a very good article on the subject here: https://en.wikipedia.org/wiki/8-bit_color

Pixels are the dots that compose the final image. For our slides and 35mm negatives we use approximately 4000 pixels per inch and this means we are almost visualising the crystals that make up the picture. We use about 1200 pixels per inch for our medium format negatives. These pictures are larger than slides and so the loss in resolution is small. We can scan at up to 9600 dpi (dots per inch) theoretically but practically there is little demand for this. Again Wiki have a good article here: https://en.wikipedia.org/wiki/Pixel

The scanned images are saved as jpeg or tif files. The tif files are uncompressed and take a lot of room on a usb stick or hard drive, jpeg files are compressed and much smaller. Read about jpeg images here: https://en.wikipedia.org/wiki/JPEG  At Saturn Films 1969 we now have one set charge of £5 for digital media no matter the size of your order. This is because we can get around  2000 jpeg images (100-200 tif images) on a 16gb drive, so the more slides or negatives we are scanning the more cost effective the storage device is.

So maybe now you know a bit more about bits and pixels and how the scanned images are saved as data on your computer. As for me, well its getting late, time for bed.