When we talk about “bits”, we are talking about the amount of tonal variation that is found in an image. Understanding the tonal values within an image will help you get the best print possible.
What is tonal value?
Every colour has a tonal range and that refers to the varying lightness or darkness of a colour. Tones are created by adding either white or black to a colour. If we look at the colour green, for example, there are many different tones of green. You can have a very light green or very dark green. So when we refer to tonal values, we are referring to the number of tonal variations available within a colour.
8-bit vs 16-bit images
The main difference between an 8-bit image and a 16-bit image is the number of tones available for a given colour. An 8-bit image is made up of fewer tones than a 16-bit image.
When shooting images in JPEG, you are limiting your bit depth as it only gives you 256 tonal values for each colour in your image. RAW images, on the other hand, can be converted to 16 bit, so we are looking at 65 536 tonal values for each tone! This allows you more freedom for editing.
Looking at your histogram whilst editing will show you how far you have pushed your images. The below image is in 8-bit and by doing basic editing you can see how each of the colour channels has been affected. The risk of over-editing on an 8-bit JPEG is that you will lose information the more you edit. Watch out for the gaps in your histogram as too many gaps will mean that you have lost original data and will not have a smooth tonal gradation. This is what we call banding. The smoother the histogram the better the tonal gradation.
Ideally, you want to shoot in RAW because it is actual unprocessed data, so do your basic editing in-camera for a fine-tuned result. Once you have got the results you want, convert your file into a 16-bit uncompressed TIFF.
Remember, when you start shooting in RAW, the file sizes are much larger. A 16-bit file is twice the size of your 8-bit file and will thus affect your processing speed, take up a lot of memory and hard drive storage. We recommend being hard on yourself, save only the best images and delete the ones that are no good or you will see yourself buying a lot of external hard drives.
So the question you should be asking yourself is, should I always edit in 16 bit? It depends on what you want to do with the file after you have edited your file and the situation.
To edit in 8 or 16 bit? Ask yourself these questions:
- What do you want from your images?
- Do you have bulk editing to do and within a time frame?
- Are you shooting for catalogues, products, web or social media?
- Do you intend selling prints and if so, what is your maximum size?
- Do you intend selling your digital file (you need to have a maximum size)?
- Does your computer become slow when you edit your images?
- Do you find yourself with multiple hard drives full of images?
- Do you see a major difference in your images once they have been edited?
Remember, this is just one of many pointers on getting the best out of your files when shooting and editing. Keep watching this space for more info and if there are any topics you would like information on, please feel free to give us a topic.
For more information on getting the best possible print, get in touch with Art of Print at [email protected]. We are ready to assist you with any printing queries.