Tutorial: how to save disk space

You probably know this issue - you take thousands of photographs on each of your photo shoots. You shoot mainly RAW. You don't have time to delete all bad photos after copying them to disk. You quickly end up with a few TB disk being completely full. You know this, don't you?

It's what happens to me every few weeks or months so I would like to share some tips with you what you can do to minimize this (or at least to slow this process down a little bit):

• If you use Lightroom, always import your photos as DNGs from memory cards instead of RAWs. One of the huge benefits of DNG files is that they are by 15% or more smaller than original RAWs! For 100 GB of RAWs you can save 15 GB of memory or more this way. But for 1 TB it becomes as much as 150 GB! Big difference. You can make DNGs even smaller by using compression but as this is related to loss of quality I'm not doing this myself.
• Convert existing RAW photos to DNGs. If you're like me, you probably still have a lot of RAWs on your disk. You can convert them from Library module in Lightroom at any time by invoking Library -> Convert Photo to DNG command. Bear in mind that any adjustments made to original RAWs would be impossible to revert after doing so. So you might consider resetting adjustments and only then convert to DNG.
• In Photoshop never ever save your intermediary results as TIFF. Use PSD (or PSB for very large photos) instead. TIFF files, especially those not compressed, can be even a few times larger than PSD files.
• In Photoshop remove any unused layers or channels before saving. They can greatly increase image size.
• In Photoshop you can also consider flattening your layers or merging visible layers. In my case I hardly ever make adjustments to an already edited photo in PSD files. More frequently I apply sharpening to an already processed photo (but for this I need only final image without any other layers) or start processing my photo from scratch. As PSDs still can be quite large (1 GB or more), you can save a lot of space this way.
• Constantly go through your TODO folders and remove photos you don't like. Otherwise you'll end up with 100k of unprocessed shots most of which you don't like at all (and for that reason will never process them). I usually take from 4000 to 8000 photos during 1 week trip. Quite a lot. As soon as I'm home I start to remove photos I don't like. At this stage I remove technically bad photos like the ones with focusing issues or much too noisy. When I start to process my photos several weeks later I remove more photos and more and more. Eventually I end up with only 100 to 400 photos left. Usually these are the best ones.
• Use cloud services. Cloud storage became very cheap these days and one of its benefits is that it's quite safe. It's more probable than your local hard drive will crash than you will loose data stored in the cloud. Another benefit is that this way your data is accessible from all over the world - you don't need to carry disks with you.