More LR5 Space Woes

So, got help around here for an issue I was having with LR telling me my disk was too full to import even though I was importing to a new (empty) drive. Figured out I needed to move my catalog/previews over to the new drive--which I did.

I am working in the catalog on the new drive--I confirmed this--but it seems LR still wants to create the previews on the old drive. Ran into this just now because I'm trying to work on some files from a job last week--which was imported to the old fuller drive. I was working on something in Photoshop (from LR) and, when I went to save the file after editing in PS, it tells me the disk is full.

I knew I'd freed up space so wondered why I couldn't save the file--I realize it would try to save the file back to the old drive because the original RAW files are there. The preview file on the old drive had been updated earlier today, which was really strange since I worked on some photos from yesterday (on the new drive). When I checked the preview file for the new drive, it hadn't been accessed since the other day.

Ok, now I'm really confused. If I'm using a catalog on Drive B but it originally resided on Drive A, why is it writing previews back to Drive A?

When working in PS, if you do it the way Adobe would expect you to, the PSD or TIFF file that is created when you off load to PS is created in the same folder as the original RAW file. So assuming that your existing RAW's are still on the really full drive that's where PS will try to save them. In this case nothing to do with your previews. Remember that by default you will be working with a 16 bit ProPhotoRGB TIFF file using no compression. For a modern 18 Mpix image thats 103 MB of file just with a single layer. Adding layers simply adds the same amount of data for each one (well maybe not so much for an adjustment layer.) Layer masks also add more data. So the size of the file you get from round tripping to PS can get very big very quickly.

You will need to move more of your images to the new drive, so that you can pass them to PS and have space to save the resulting file.

Alan