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Submission guidelines and file size

qc submissions file size quality control

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#1 Alamy

Alamy

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Posted 19 February 2013 - 11:39 AM

We've found our required file size for submitting Jpegs can cause confusion with some contributors.

To set the record straight, yes we want you to send Jpegs and not Tiffs. 

The reason for this is that we provide our clients with Jpeg files to download. This has been the industry standard for a long time now. We know Jpeg is a lossy format, however, to the naked eye there is no visible difference between a high quality Jpeg and a Tiff file. Client's can simply download a Jpeg, save it as a Tiff, and work away on it saving as many times as they like without loss in quality. It really is that simple!

Now moving on to file size. Jpeg is a compressed file format. The compressed file size (size on disk) varies with picture content and isn't important. What’s important is the uncompressed (opened) file size. The opened file must be at least 24MB at 8 bit to be successfully processed and arrive in QC (Quality Control). Typically a 24MB 8 bit Tiff file will be between 2MB - 5MB as a Jpeg. Remember, we do not want a Jpeg 24MB in size as that would be ridiculously large when uncompressed (opened)! One thing you don’t want to do is work on your images whilst they are in Jpeg form. Saving a Jpeg as a Jpeg damages the file, this is due to the fact you are recompressing an already compressed file. 

Now, there are various ways of doing this, for us an ideal workflow example would be:

* 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, then send it to us. Remember, the Jpeg is the compressed size so this will typically be between 2MB - 5MB

 

Alternatively you can simply work on your images as above in RAW format and export a Jpeg to send to us.

There are many digital cameras on the market that produce native uncompressed file sizes above 24MB so you will not need to do the above for those. This is the same for film scans
Remember to also inspect your images carefully in accordance with our submission guidelines, found here:

http://www.alamy.com...raphy-guide.asp

Alamy


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Also tagged with one or more of these keywords: qc, submissions, file size, quality control

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