I've searched this topic on NPN and found some info, but some of it seems contradictory, and I still have some questions.
I'm hearing that the PSD (photoshop document) format is becoming more popular than the long-lived TIF format, and also that at some point TIF might be phased out.
While both are Adobe formats, it's my understanding that TIF is publicly documented while PSD is proprietary. It's also my understanding that PSD is more nimble than TIF because a person can open an old PSD and do things with layers that aren't possible with TIF. But my reading also indicates that, since CS2, TIF files can be saved with layers as well. And a PSD has compression inherent in the format, while with a TIF it only compresses if you want it to. My reading indicates that PSD's lossless compression yields smaller files than TIF, but how is lossless compression even possible?
I hope some of you techno-assassins in here can comment on this. I've been using TIF all along, converting my RAW or JPEG captures to TIF and working on the TIF files.
But if PSD is just as good, or even better in some ways, and if it's going to be the future preferred format, I'll switch in a heartbeat.
Anybody got their fingers on the pulse of the future?
Steve, good question. I have been wondering the same thing. Like you, I currently save all my processed files in uncompressed TIFF preserving all layers. The ability to save the layer structure is a big bonus of CS3. It allows me to modify later as needed. The most common thng is to remove copyright watermark or modify sharpening. But I digress.
If PSD is accepted by the industry as a standard, this may be the way to go. I hope others who are more in the know respond.
I'm getting a mixed read from the GA's I've talked to. In my experience they know a whole lot more about Photoshop than do most photographers, and in fact I think the program was originally developed for them rather than the rest of us.
But there's a familiar ring among the GA's. The traditionalists are sticking to TIFF while the younger set are going with PSD. If I was going to be around long enough and had to bet on the future, as the older GA's retire the younger replacements are going to set the standard.
In the meantime, you'll encounter GA's that prefer one or the other and you'll have to meet their needs in submissions. Has anyone compared files saved as PSD's, then converted to TIFF at a later date, with those saved originally as TIFF's? And visa versa? Any demerits?
Steve - One thing to think about is that, until PS stops supporting TIF (which isn't all that likely to happen in the next few years, given its popularity) you could always open and re-save your files. Might be a pain, but it would save everything and you wouldn't have to worry about it for now.
Other than that, I don't really know anything about the differences between the files, except that I don't think PSD files use compression and are about the same size as uncompressed TIFF files (it may depend on what exactly is stored in the PSD?). Lossless compressed TIFF is much smaller though (using the LZW algorithm), although I haven't saved any layered TIFFs.
...how is lossless compression even possible?
I can help a little here Steve. At a very basic level, compression simply takes repetitive data and summarizes it. For instance, if you have 25 pixels in a row that all have value 148, rather than storing 25 separate numbers that are all 148, you can store just the two - 25 and 148. Then when you uncompress you reproduce the 25 separate values. So assuming you use 3 bytes per number, you've just gone from 75 bytes to 6 bytes.
In reality, it's a lot more complex than that with different, although similar, techniques. Lossless compression may do something similar, but use statistics and prediction to not quite reproduce the original pixels, but compress them even further. Here's a couple of pages if you want to read more :
Thanks for the start, everybody. All good thoughts and info.
Hank, my wife has been a graphic artist for going on 30 years, and grew into the business with Photoshop. She knows far more than I ever will about it, further proof that you're right about GAs and Photoshop.
I just need to know how to make pictures look good, and that takes but a small percentage of PS's functions.
Discussion
5 repliesI'm hearing that the PSD (photoshop document) format is becoming more popular than the long-lived TIF format, and also that at some point TIF might be phased out.
While both are Adobe formats, it's my understanding that TIF is publicly documented while PSD is proprietary. It's also my understanding that PSD is more nimble than TIF because a person can open an old PSD and do things with layers that aren't possible with TIF. But my reading also indicates that, since CS2, TIF files can be saved with layers as well. And a PSD has compression inherent in the format, while with a TIF it only compresses if you want it to. My reading indicates that PSD's lossless compression yields smaller files than TIF, but how is lossless compression even possible?
I hope some of you techno-assassins in here can comment on this. I've been using TIF all along, converting my RAW or JPEG captures to TIF and working on the TIF files.
But if PSD is just as good, or even better in some ways, and if it's going to be the future preferred format, I'll switch in a heartbeat.
Anybody got their fingers on the pulse of the future?
If PSD is accepted by the industry as a standard, this may be the way to go. I hope others who are more in the know respond.
But there's a familiar ring among the GA's. The traditionalists are sticking to TIFF while the younger set are going with PSD. If I was going to be around long enough and had to bet on the future, as the older GA's retire the younger replacements are going to set the standard.
In the meantime, you'll encounter GA's that prefer one or the other and you'll have to meet their needs in submissions. Has anyone compared files saved as PSD's, then converted to TIFF at a later date, with those saved originally as TIFF's? And visa versa? Any demerits?
Other than that, I don't really know anything about the differences between the files, except that I don't think PSD files use compression and are about the same size as uncompressed TIFF files (it may depend on what exactly is stored in the PSD?). Lossless compressed TIFF is much smaller though (using the LZW algorithm), although I haven't saved any layered TIFFs.
I can help a little here Steve. At a very basic level, compression simply takes repetitive data and summarizes it. For instance, if you have 25 pixels in a row that all have value 148, rather than storing 25 separate numbers that are all 148, you can store just the two - 25 and 148. Then when you uncompress you reproduce the 25 separate values. So assuming you use 3 bytes per number, you've just gone from 75 bytes to 6 bytes.
In reality, it's a lot more complex than that with different, although similar, techniques. Lossless compression may do something similar, but use statistics and prediction to not quite reproduce the original pixels, but compress them even further. Here's a couple of pages if you want to read more :
Lossless Compression on Wikipedia
Lossy Compression on Wikipedia
Hank, my wife has been a graphic artist for going on 30 years, and grew into the business with Photoshop. She knows far more than I ever will about it, further proof that you're right about GAs and Photoshop.
I just need to know how to make pictures look good, and that takes but a small percentage of PS's functions.