File Sizes

[ShawWellPete]

Hi all,

Here's something that has been confusing me. I take RAW photos with my Minolta 7D that are about 9 Meg in size. I use Adobe lightroom and CS2. In lightroom If I right click on a Raw file and select "edit in CS2" a TIFF or PSD file is created to edit in PS. Either way the file that is created is about 40 Meg. That is before I add any new layers or, in fact, do anything else with the image.

Why are the TIFF or PSD files so big? If I get lightroom to convert the files to DNG when they are imported they come in at about the same size as the raw files.

Is there a more efficient way of editing files in CS2?

 

[Woodsy]

Is effieciency the issue? or is it limited disk space?

 

[ShawWellPete]

Limited disk space I guess - I am running it all on a Macbook pro with 120Gig. I have about 30 Gig left which could be quickly used up if every time I edit a photo, I end up with such large files...

 

[Joe T]

RAW (or DNG) files have a certain amount of compression.

TIFF files are totally uncompressed:

8 bit tiff = 24 bits to each pixel (8 red, 8 blue and 8 green)

6 million pixel image = 6,000,000 x 24 = 144,000,000 bits

1 byte = 8 bits

144,000,000 bits = 18,000,000 bytes

Or just under 18 mega bytes (million bytes, approx).

Does that make any sense?

 

[ShawWellPete]

RAW (or DNG) files have a certain amount of compression.

TIFF files are totally uncompressed:

8 bit tiff = 24 bits to each pixel (8 red, 8 blue and 8 green)

6 million pixel image = 6,000,000 x 24 = 144,000,000 bits

1 byte = 8 bits

144,000,000 bits = 18,000,000 bytes

Or just under 18 mega bytes (million bytes, approx).

Does that make any sense?

Hi Joe, and I have Lightroom set to 16 bit hence my 40 Meg files (36Meg + exaggerate a bit)

I guess the first thing I do is bring that down to 8 bit. Will I notice a drop in quality?

Thanks for the reply by the way.

 

[Joe T]

8 bit should be pretty good imo.

 

[ShawWellPete]

Cool - thanks for your help

 

[Woodsy]

yup, 8 bit is fine tbh.

My advice, for an easy solution:

Buy a large capacity external HDD on USB 2. do all your editing locally then once you have done a batch of editing or what ever, transfere it all to the external. this way you still ge the speed of editing locally, and the external will easily be fast enough to view from. Can get a cheap caddy (£15 orso) and a 500GB Seagate or similar spec disk for around £80. Dont get a cheap hard disk, they are not worth the little you save. Get a good brand disk and have the peace of mind of it lasting a long time and not failing. A lot of people will say the cheap ones are fine, and in most cases they are, but alot more of them fail than the more expensive disks.