How we scan film
Change all this t bullets because millenial TLDR
WHICH SCAN SIZE Small 4.5, Standard 18 or Archive 48+Mb?
Good question and we'll always ask "What are you using it for?" If you just need to have a quick record to use on Facebook or send to friends by email then the smaller "4.5Mb" file size will be ideal. However, if you intend to crop out areas of the print - perhaps removing background or zooming in to a face in the crowd, then remember you are throwing away information. You cannot then expect a postage stamp size image to stretch to a postcard size without some effect on quality: you will get fuzzy edges and a blurry picture.
Today we recommend "18Mb" as a standard size because it offers more flexibility if you decide to crop or order a bigger print. A modern computer will be untroubled by such a file size and will not take up too much hard drive space if stored as Jpeg.
"48+Mb" is a good size if you want to get serious with image manipulation or need a real archive quality file size. We save these at 300dpi because we anticipate they may be needed for reproduction at magazine quality, which still demands this resolution as a standard.
Our scanner outputs fixed files sizes depending on the negative area, which is why the different formats of 120 film produce different file sizes. The best way to measure the scan size is looking at the pixel dimension not the size it occupies on your hard drive. Pixel dimensions can only be measured in a sutable software program such as Lightroom or Photoshop.
Our equipment scans film at a resolution to produce a file size in pixels, not dpi. In referring to quality, dpi has no direct bearing on quality. It would be like saying the grass on a football pitch is three hundred blades per inch without saying how big the pitch is - is it a small school pitch or Wembley sized arena? It is always the number of pixels that determines file size, not how they are arranged.
THE VERY USEFUL JPEG (JPG)
In the old days computer storage was expensive and the Jpeg, because it compresses file size when closed, was an essential tool to balance quality against storage cost. These days we worry less about storage costs but we are all subject to the limitations of broadband connections. Sending full size Tiff files is much slower than Jpeg files and the Jpeg format was specifically designed for image files.
File size describe, not the amount of space the files occupies on a hard drive, but the file size in pixels when it is open. Our 4.5Mb Jpeg file size is 1545x1024 pixels: when the file is closed it may only take up 300kb of storage space. Nothing has been lost - it is still 4.5Mb, but the smaller closed size makes it much quicker to send - in the case 4500kb / 300kb = 15 times faster.
When a Jpeg file is saved, you are often prompted for the level of compression you'd like from 1-10. At The Darkroom we only choose the top quality option, in fact our software does not allow for any other size - it is a fixed maximum quality.
The only Jpeg rule is this: If you are working on an image over a number of sessions then save in either a Tiff or Photoshop format. Both formats are 'non-lossy' and will preserve all the fine detail and subtle variations that successive savings as Jpeg might degrade. Once you have finished your work and are happy with the result, then why not save as a top-quality Jpeg, if this saves storage space on your hard-drive?
BIG IS NOT (NECESSARILY) BEST
If you have a digital camera with a 16.2Mb sensor, the resulting files will be around 16.2 x 3 = 48.6Mb in RGB. If you want to order a 4x6 print then sending such a file via broadband might take 20 minutes as a Tiff: as a good quality Jpeg the file size might be 8Mb and take only 5 minutes to upload. Better still, downsize the image to 4"x6" @ 300dpi and send a 1.3Mb file. A few sensible housekeeping rules in managing file types and size will make your life quicker and less frustrating!