Saving as Tiff file size

Hi,

I'm new to this forum and have a question I can't find the answer to on the net.
I'm shooting with a 550d in RAW giving me a typical file size of around 20mb. I've just finished processing one of these images in CS5 and saved it as a Tiff. When I checked on the file size in explorer, it's now 206mb!

I've compressed the file to Tiff ZIP in the save option box which appears but that still leaves it at 100mb! I've been saving all my files as Tiffs over the last few months but can't afford the HDD space at this rate.

I've been told to save files as Tiff's in case you ever want to come back and do more editing a few months down the line. If you save as JPEG, you'll lose a lot of quality?

Can anyone offer some advice as to how I can keep an edited file size to an equal or lesser size than the original RAW?

Thanks in advance.

Well, yes, this is the issue with the tiff format as well as the Adobe psd format -- huge file sizes, especially once you do editing in Photoshop that involves layers.

Fortunately, as technology grows and pumps out these devices with higher digital resolution, hard disk drives "grow" in order to accomodate this. So, digital photogs are driven to update our hard drive space to keep up. Fortunately, hard drive space has become much less expensive over the years. So, it's common to have not just a hefty internal "data drive" but also use at least one external drive along with the needed external backup drive. Drive sizes of at least 1 TB are getting pretty normal these days.

And then, you still want a workflow that is efficient. I myself do most of my processing in the Raw processor and don't use the Photoshop editor for an image unless I really need to. This suits the photography I do just fine, and I don't end up with all these tiffs scattered in my library. I use my Raw processor to export for the Web and, if needed, for an external printer, all of which is done using jpegs which can be archived on an external drive or even discarded since the Raw processor keeps all the editing data.

As to when you do need Photoshop, yeah, it has for years been considered "best practice" to have a 16 bit "project file" for meaningful edits that you will want to revisit, for the reason you mentioned. Whether this is always necessary is a workflow choice that you have to make. If you are really "finished" with the image, well, maybe not. If you have only "light" touchups that you will do in the future, or special things like sharpening or applied filters or other things that won't benefit from the 16 bit file, then, 8 bits can certainly cut down on the file size. It's up to you.

The 550D is 18 MP.
A 16 bit tif has 48 bits in each pixel (16 x 3 color channels).
48 bits = 6 bytes.
18 million x 6 bytes = 103 MB, which is the size an uncompressed 16 bit tif will be if it has a single layer. Every time you add another layer you increase the size of the file. So to reduce file size you have to flatten before saving to bring it back to 103 MB, convert to 8 bit to reduce it to 51.5 MB, compress it with zip or LZW compression or save it as a compressed jpg.
TANSTAAFL

Thanks guys. I've just had a look through the save options and can't see how I would compress from 16 bit to 8 bit. I'm not really clued up on this but as I understand, my RAW is 8 bit, when I save as Tiff that increases to 16 bit? This increase obviously causes the file size to increase.

How do I flatten the layers? Once this is done, can you still access them. The reason I ask is because I place my signature on all the photographs I edit. I put this on a separate layer (which is only slightly bigger than the signature itself) so I can remove it easily if I need to print.

No, actually the RAW is 14 bits x 1 channel. Moving to PS the rendered RGB image is a 16 bit bitmap which can at any time be converted to 8 bit. Somebody more familiar with PSCS can tell you where to find that function. Flattening the image before saving it is not reversible.

In the PS editor you can convert to 8 bits in the Image/Image mode menu.

To flatten an image (all layers) you use the Image/Flatten Image menu choice.

There is also an option to Image/Merge layers which people often use when they are "finished" with work on a group of layers and so they basically flatten just the layers they are done working with.

But, flattening and merging can't be revisited once you save/close the file. So, like I said earlier, thought needs to be given to your workflow!

Thanks for your help, it's much appreciated. Looks like I can add another hard drive on to my ever increasing photography budget. I knew I should have taken up skimming pebbles as a hobby; far less expensive

16bpc is only needed if you do (big) luminance / color adjustments in Photoshop or use a wide gamut color space.
If you process sRGB files, in most cases 8bpc is plenty.

Thanks. By converting to 8bit, do you just mean saving as a Tiff Zip in the save options box. I assume this has no effect on the image quality. It just compresses it for storage purposes?

http://www.earthboundl​ight.com …sus-adobe-rgb-debate.html

There's also info on bit depth.

Zip and 8 bit are completely unrelated. A google search will help educate you. 8 bit is all you need if you do most of your processing in ACR/RAW. ZIP is lossless compression. Personally I use psd files, slightly less compatible but they're always compressed.

Turn off the "Maximise PSD/PSB compatibility" in photoshop file handling preferences if you use PSD and only use Adobe products with psd files. That creates a flattened extra layer.

Also use adjustment layers when you can. They take effectively no space.