i think most digital camera files are big enough to get accepted in Alamy, it seems some people still get confused seeing the 24mb uncompressed file size.

It used to be 48mb? but 24mb uncompressed size is achieved by mostly 6MP camera.

just open up the jpg in photoshop, maximise the jpg windows in photohshop and you can see a 'tab' under as 'Doc:34.9M/34.9' something like that, that's uncompressed jpg size. the one alamy refers to.

I thought I wanted to put some material on Alamy until I read the requirements.  I sell on the micro sites, and they all warn against interpolating and upsizing.  I was surprised to see that Alamy requires it.  So is it really worth upsizing, and keeping a separate folder in my system just for Alamy material?  If so, what's the most efficient way to upsize that you've found?  (I'm using Photoshop CS4.)

I normally start my workflow by batch processing to create 8-bit tiff files from my raw images.  The tiff files are usually in the 25mb range.  The resulting jpg files are normally in the 5 mb range.  Assuming that you upsize the tiff files, how much would you upsize them to result in a 24+ mb jpg file, per the current Alamy requirements?

Thanks in advance for the input.

It used to be 48mb? but 24mb uncompressed size is achieved by mostly 6MP camera.

Not quite. You need about 8,4 MP.
I have to upsize my Canon 30D files (8,2 MP) a tiny little bit to reach the 24 MB uncompressed.

To the OP: Your Tiff file size should be exactly what you are looking for (uncompressed file size), so if that is 25 MB you should be fine without upsizing.

(Here's the calculation:
24 MB = 24x1024x1024 Bytes = 25.165.824 Bytes.
As a 8-bit RGB file needs 3 Bytes (uncompressed) per Pixel, you end up with 25.165.824 / 3 = 8.388.608 Pixels, i.e. roughly 8,4 MP.
Attention: Cameramakers normally seem to calculate "Mega"pixel = "1 million"pixel, in contrast to IT folks where "Mega"byte = "1024x1024"byte.
And forget about looking at JPG file sizes, the compression algorithm can lead to vastly different file sizes for different images of the same uncompressed size.)

Far too easy for people to make it so complicated. If you have a fairly modern camera, you already have 24MB files and don't need to upsize anything.

Alamy Link which by the way is a sticky on the forums. Not hard to find...

http://alamy.com/forums/default.aspx?g=posts&t=4337

* Convert your image into an 8 bit Tiff file (save as, Tiff)
* In an image editing program such as Photoshop, upsize the image to a minimum of 24MB (if you need to).
* Make any alterations as needed, inspect the image carefully at 100%
* At the very last step save your image as a Jpeg and send us that Jpeg. Remember, the Jpeg is the compressed size so this will typically be between 2MB-5MB

If the file is already large enough, you don't need to make it larger or smaller, just leave it the same!

Hope that make it easier to understand and find.

I have uploaded a batch of images this week, some of which taken with a 7.1MPix camera, what required a little upsizing, all accepted. If the original is sharp (not sharpened!), the required upsizing works fine.

Until now I have not got any rejection from Alamy. The smallest sizes I have submitted were about 6 MP (cropped out of a 8,2 MP photo) before upsizing.

Thank you so much, Pete (RacePhoto).  I got the impression from reading the Alamy guidelines that they wanted uncompressed jpg files with a minimum file size of 24mb!  I thought it was rather odd, and I thought perhaps they accept only high-end medium- or large-format camera material.  It turns out that my routine work flow matches their requirements precisely, so I'll upload my test shots pronto.  Thanks again to everyone who took the time to read and reply.

Yeah, you're the first one to ask.

Don't feel bad, it's been a topic every week and the regulars on the Alamy forum are now down to giving smart ass answers, (justifiable in most cases) because the people who ask there, have ignored the sticky right above their question and never took the time to search, which would have found about a zillion threads asking the same things.

I just refer to the links because then there's no doubt who the answer is coming from. Alamy! LOL

The whole difference that confuses the issue and mystifies people is really quite simple.

JPG File Size on Disk (which is the one that's 2-3-4MB)
vs
Uncompressed TIF file size of the image (which is 28MB for an 10MP camera)

8MP camera will be about 23.9 (just a smidgen under if I figured it right?)

But if you check, a Canon 20D is an 8.2MP camera, 3504 x 2336 which comes out to 24.6MB TIF.

If you shoot Nikon you'll have to calculate for yourself. But most editing software will show the actual file size, down in a box in the corner if that's selected, instead of one of the other choices. I leave mine on uncompressed file size, just for checking.

All of this leading to, most 8MP cameras won't need to be upsized, if you fill the frame with the image and 10MP cameras will leave a little crop room.

Here's a nice chart. Notice that all pixels are not created equal. The size of the pixels does make a difference. I'm not especially fond of pixel packing (cramming more on a same size sensor) For that reason, someone carrying a camera for personal use, might find a real bargain with a 10D? Same for people shooting micro who don't need giant images, but can use  and appreciate the large sensor with big pixels on a DSLR that would cost less than some newer camera. Especiall much more useful than a P&S or any pocket camera.

Don't own one, so I can't say, but according to the chart (if we are to believe it?) the 30D is an 8.2MP sensor and the final image should be. 3504 x 2336, which is - aw dang nab-it. You just pointed out another flaw. When people had to have 48MB files and uploaded exactly 48MB files, they would fail! Good catch. I have had some 48.2 pass, and with the same problem, exactly 24MB files Will Fail the size test.

Different software, especially the checker on Alamy, use real size, not the mathematical size printed in spec. sheets.

You are absolutely correct, a 20D or 30D produce a 23.4MB image, which is undersized!

Thanks for the correction.

Quote from: RacePhoto on November 13, 2010, 04:24

8MP camera will be about 23.9 (just a smidgen under if I figured it right?)

But if you check, a Canon 20D is an 8.2MP camera, 3504 x 2336 which comes out to 24.6MB TIF.

Not quite right, see my post above. I need to upsize my files from my Canon 30D (same sensor as the 20D) to 3550 Pixels on the long side.
Without upsizing the uncompressed size is 23,4 MB (as shown in PS).

Quote from: RacePhoto on November 13, 2010, 04:24

All of this leading to, most 8MP cameras won't need to be upsized, if you fill the frame with the image and 10MP cameras will leave a little crop room

You'll need about 8,4 MP if you want to avoid upsizing.