Really fat Photoshop file?

[jbgibson]

New user aquarits seems to be having trouble with ps file size. I don't use PHotoshop, but I have a sneaking suspicion the map aquarits has as a WIP has no business being ThAT big - 12gb for less than 2000 pix square . Am I right, wrong, or It Depends?

I figured since English isn't aquarits' first language maybe there was something obvious ( to a PS user ;-) ) wrong in the handling of the bitmap thread they reference having used.

[ManOfSteel]

12 gigabytes for a 2000 pixel square image? I can't imagine. However, the dimensions are not so much the problem...it's what's in the layers that he's made that make up that 2000 pixel square image. It's the complexity of the data that enlarges the file. For instance, if I fill a 2000 by 2000 pixel layer with a single color (every pixel the same) that will barely make a dent in the file size because Photoshop will do some shorthand and just say to itself "This color...4,000,000 times". But if you fill that layer with intricate detail, or gradients of color, or clouds, or effects that influence other layers, that's a whole lot of calculations that have to be done to each pixel in the layer and the file size will get really big really fast.
But 12 gigabytes? We'd have to see what he's done in that file to figure out why it's so big.
Just to give you an example, my Planet Eben political map has approximately 1300 layers. Most of them are text labels and there aren't many color gradients. The dimensions are 8200 by 4100 pixels and when the file is open it's 2 gigabytes. Saved and compressed it's 346 megabytes.

[Gamerprinter]

That just sounds like poor image file management. If I were working on a multi-layered PS design I would save the file at each major stage of design. Then I'd flatten the PS image, so all layers become one layer, saved as a different file name, before I'd move on to the next stage of multi-layer development. In the end I might have a half dozen separate files, each containing a flattened version of the previous stage. There would always be a version of unflattened at various stages so I could go back and edit if I need to. The final map image might be 10 or 15 MB total. Besides whoever the final user of the map, has no need of a multi-layered design. Flatten it all, and the file size becomes small, relatively speaking.

[Jaxilon]

What resolution are you doing this in? 300 pixels/inch or what? If you are going for super high resolution it's going to make a big file really fast.

I usually end up creating a stripped down file myself because after a while you just have too many layers going on and if you don't need to revisit them you may as well create a new flattened base and work from there. It also provides you with a series of backup files you can go back to in case you have a catastrophe.

[Vellum]

So how does this flatten file actually work in practice. Let me see if I can ask this correctly. If I save a file with all its associated layers etc as a "base file" (one with all elements intact) and then flatten it. Say I work on the flattened image but I need to correct something or modify the base file, I then loose all the work placed on the flattened image, so what's the advantage? I understand flattening and lowering resolution for finished product but I really don't have a handle on it for in progress work. Anyone care to explain that a bit more? Jax I get the idea of multiple file save increments

[Jaxilon]

So how does this flatten file actually work in practice. Let me see if I can ask this correctly. If I save a file with all its associated layers etc as a "base file" (one with all elements intact) and then flatten it. Say I work on the flattened image but I need to correct something or modify the base file, I then loose all the work placed on the flattened image, so what's the advantage? I understand flattening and lowering resolution for finished product but I really don't have a handle on it for in progress work. Anyone care to explain that a bit more? Jax I get the idea of multiple file save increments

While you could use the "flatten" feature and slam everything down to one layer what I usually try to do first is just "merge down" as many layers as I can while still leaving me some room to modify things. For example, I might merge all my forest layers or my mountains or anything I am not planning on changing again. Doing this I might take 15 layers and reduce them to 8 or something. I then 'save as..' to a new file name that I work on from then on.

Now, lets say you needed to go back to your original to make a change you couldn't make on your new version. You would open up the original, make the changes, turn off all the unmodified layers and then save or cut paste only the layers you needed back into the new version, getting rid of the layers they replace of course. That is like worse case scenario though. If you are like me, I'm a layer hoarder so you may find you don't miss all those extra layers.

That's just how I've done it in the past, I'm sure there are some folks here who do it quite often and they may have some better methods. I do know it will take a huge file size and greatly reduce it. Just make sure that when you merge down your layers it looks correct because mergeing down doesn't always act the way you would expect. If it doesn't look right just undo the last merge and that's as far as you can go merging that particular layer.

I hope this helps.

[Clercon]

I guess that the map might be in 32 bit colour mode, that will make the map much bigger. No need to use anything else then 8 bit colour mode.

[Midgardsormr]

Jax: The map is 2000 pixels square. Since the pixel dimensions are fixed, then dpi makes no difference, as that is only metadata. I can make a 2000 pixel square image at 10 dpi or at 1,000 dpi, and the file size will be exactly the same. The only things that will change are the size it prints out on paper and what Photoshop might do when you tell it to zoom to 100% (there's a setting in there somewhere that determines whether you see 1:1 pixels or 1:1 inches. The default is to show the pixels, which minimizes distortion from resampling.)

I suspect that Clercon is correct, and that the image is being worked in a deep color space. I would add a caveat, though, that there is usually no need to work at greater than 8-bit, but sometimes the extra precision of 16-bit mode is helpful for height maps, and 32-bit mode can make color operations almost non-destructive. If you don't have a specific reason for needing that extra precision, though, then stick with 8-bit.

[Jaxilon]

@Midgardsormr, You are correct. I had that goofed up in my head, thanks for pointing it out.