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How to identify uncompressed file size


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I submit photos to Alamy and need to check the uncompressed file size before sending. I can do this in Photoshop (it appears at the bottom of the document) but am trying to wean myself off Photoshop. I can see the document size at the top of an image in Affinity Photo, but it does not correspond to the size in Photoshop.  For example:

a dng image in Lightroom has a file size of 12.51 MB

If I open this in Photoshop the uncompressed image size is shown as 72.8 MB.

If I open in Affinity Photo it creates a tif file with a size of 12.72 MB. If I export this to a jpg the actual file size is 12.72 MB. If I re-open this in Affinity Photo the file size is shown as the same, the compressed file size.  I need to identify the uncompressed file size as this is the measure that Alamy uses.

Any idea where I can find this information in Affinity Photo? Or am I stuck with Photoshop?

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AP does not show that info (IMHO).

Export your photos as uncompressed TIFFs and check the file size in Finder (or windows equivalent).

Alamy size requirement is rather relaxed, meaning they accept smallish images (too); normal older generation DSLR (here Nikon D60) generates about 2613 X 3900 pixel image (note that AP generally preserves some border pixels that other apps crop and throw away) and size of that uncompressed is 30 MB. Plenty more than Alamy requirement (17 MB).

As AP JPEG engine is not highest class it may well be preferable to export images to TIFF and use separate app to batch compress to JPEG. I would recommend XnConvert. (When you have checked the uncompressed file size in your typical image you can change TIFF to lossless compression and save a few megabytes (or GBs) in disk space.)

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6 hours ago, stuartbarry said:

Any idea where I can find this information in Affinity Photo?

The file size does not really exist until you have exported the file (or at least set up the export), because the kind of file (JPG, PNG, TIFF) and the export options you choose determine that information. So, you go into File > Export, choose the options you want to use, and then check the estimated file size:
image.png.36533f753866fe33de21a1814b0fb31c.png

-- Walt
Designer, Photo, and Publisher V1 and V2 at latest retail and beta releases
PC:
    Desktop:  Windows 11 Pro, version 23H2, 64GB memory, AMD Ryzen 9 5900 12-Core @ 3.00 GHz, NVIDIA GeForce RTX 3090 

    Laptop:  Windows 11 Pro, version 23H2, 32GB memory, Intel Core i7-10750H @ 2.60GHz, Intel UHD Graphics Comet Lake GT2 and NVIDIA GeForce RTX 3070 Laptop GPU.
iPad:  iPad Pro M1, 12.9": iPadOS 17.4.1, Apple Pencil 2, Magic Keyboard 
Mac:  2023 M2 MacBook Air 15", 16GB memory, macOS Sonoma 14.4.1

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7 hours ago, walt.farrell said:

The file size does not really exist until you have exported the file

But the uncompressed size should be easily calculated (as it is calculated just pixel dimensions X bit depth)... but yes, export window shows this info.

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5 hours ago, Fixx said:

But the uncompressed size should be easily calculated (as it is calculated just pixel dimensions X bit depth).

No, that's the size in memory, and it has little relevance to the exported size, which will depend strongly on the export format (TIFF, PNG, or JPG) and (especially for JPG) the export options that are chosen.

-- Walt
Designer, Photo, and Publisher V1 and V2 at latest retail and beta releases
PC:
    Desktop:  Windows 11 Pro, version 23H2, 64GB memory, AMD Ryzen 9 5900 12-Core @ 3.00 GHz, NVIDIA GeForce RTX 3090 

    Laptop:  Windows 11 Pro, version 23H2, 32GB memory, Intel Core i7-10750H @ 2.60GHz, Intel UHD Graphics Comet Lake GT2 and NVIDIA GeForce RTX 3070 Laptop GPU.
iPad:  iPad Pro M1, 12.9": iPadOS 17.4.1, Apple Pencil 2, Magic Keyboard 
Mac:  2023 M2 MacBook Air 15", 16GB memory, macOS Sonoma 14.4.1

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1 hour ago, walt.farrell said:

No, that's the size in memory, and it has little relevance to the exported size [...]

It has every relevance to the topic of this thread, though.

The OP is submitting to Alamy.

https://www.alamy.com/contributor/how-to-sell-images/guidelines-for-submitting-images/?section=3

Quote

 

How to pass QC:

[...]

  • JPEGs
    You can shoot or illustrate in whatever format you like, but you’ll need to submit your images to us as JPEGs.
  • File size of over 17MB (when uncompressed/open)
    Your JPEG file is likely to have a compressed size of 3-5MB. Opening a JPEG in an image program such as Adobe Photoshop will show you the uncompressed/open file size.

 

 

For an 8 bits per channel RGB image (which will be decoded from a JPEG of a photo), the uncompressed size is calculated as quantity of pixels * 3 channels * 1 byte.

Photoshop displays that size and AP does not. AP displays the quantity of pixels only, which the OP confused for the quantity of bytes (of a 16 bits per channel RGB image) seen in Photoshop.

 

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21 hours ago, stuartbarry said:

I submit photos to Alamy and need to check the uncompressed file size before sending. I can do this in Photoshop (it appears at the bottom of the document) but am trying to wean myself off Photoshop. I can see the document size at the top of an image in Affinity Photo, but it does not correspond to the size in Photoshop.  For example:

a dng image in Lightroom has a file size of 12.51 MB

If I open this in Photoshop the uncompressed image size is shown as 72.8 MB.

If I open in Affinity Photo it creates a tif file with a size of 12.72 MB. If I export this to a jpg the actual file size is 12.72 MB. If I re-open this in Affinity Photo the file size is shown as the same, the compressed file size.  I need to identify the uncompressed file size as this is the measure that Alamy uses.

Any idea where I can find this information in Affinity Photo? Or am I stuck with Photoshop?

 

AP doesn't show that info, but the context toolbar does show the quantity of pixels when the View Tool (the hand icon) is active.

You'll be submitting an RGB JPEG to Alamy, so just multiply the quantity of pixels by 3 to get the quantity of bytes for the uncompressed image.

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4 hours ago, walt.farrell said:

No, that's the size in memory, and it has little relevance to the exported size, which will depend strongly on the export format (TIFF, PNG, or JPG) and (especially for JPG) the export options that are chosen.

That is also the size of uncompressed image saved to disk, and thus has maximum relevance. Do not mix compression options into this 🙂

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56 minutes ago, Fixx said:

That is also the size of uncompressed image saved to disk, and thus has maximum relevance.

The size on disk is definitely related to the format of the file. Exporting uncompressed as a TIFF will give a different size than exporting as a PNG or a JPG.

-- Walt
Designer, Photo, and Publisher V1 and V2 at latest retail and beta releases
PC:
    Desktop:  Windows 11 Pro, version 23H2, 64GB memory, AMD Ryzen 9 5900 12-Core @ 3.00 GHz, NVIDIA GeForce RTX 3090 

    Laptop:  Windows 11 Pro, version 23H2, 32GB memory, Intel Core i7-10750H @ 2.60GHz, Intel UHD Graphics Comet Lake GT2 and NVIDIA GeForce RTX 3070 Laptop GPU.
iPad:  iPad Pro M1, 12.9": iPadOS 17.4.1, Apple Pencil 2, Magic Keyboard 
Mac:  2023 M2 MacBook Air 15", 16GB memory, macOS Sonoma 14.4.1

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17 minutes ago, walt.farrell said:

The size on disk is definitely related to the format of the file. Exporting uncompressed as a TIFF will give a different size than exporting as a PNG or a JPG.

I do not think there is such thing as uncompressed PNG or JPEG. There is no relevance to the problem at hand to talk about PNG and JPEG. 

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2 hours ago, Fixx said:

I do not think there is such thing as uncompressed PNG or JPEG. There is no relevance to the problem at hand to talk about PNG and JPEG. 

It is relevant, because Photo has no idea what format you might be planning to use when you Export, until you get to the Export stage. You might choose to export an image as a PNG, JPG, TIFF, PDF, or any other format supported by Photo. So the "uncompressed file size" has no meaning until you choose the export format. And once you've done that, Photo will show you the estimated size (and at that point you also have settings that let you determine how it will be compressed, if at all).

-- Walt
Designer, Photo, and Publisher V1 and V2 at latest retail and beta releases
PC:
    Desktop:  Windows 11 Pro, version 23H2, 64GB memory, AMD Ryzen 9 5900 12-Core @ 3.00 GHz, NVIDIA GeForce RTX 3090 

    Laptop:  Windows 11 Pro, version 23H2, 32GB memory, Intel Core i7-10750H @ 2.60GHz, Intel UHD Graphics Comet Lake GT2 and NVIDIA GeForce RTX 3070 Laptop GPU.
iPad:  iPad Pro M1, 12.9": iPadOS 17.4.1, Apple Pencil 2, Magic Keyboard 
Mac:  2023 M2 MacBook Air 15", 16GB memory, macOS Sonoma 14.4.1

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Thank you to all who replied. This does seem to be a fairly active forum, which is great. To summarise:

I have had 000s of photos accepted by Alamy, but I have to follow their rules. Only once or twice in those thousands have I been less than careful and had photos rejected for file size (mostly something that I have cropped). Whatever the logic of this their rules state a minimum of 17MB uncompressed file size and suggest using the figure shown by Photoshop at the bottom of the document. All images submitted to them are jpg, so I convert them first, then check the size. Because every photo compresses differently looking at the actual file size is not a good guide. Any jpg of 6MB or more is generally safe, but for the rest I have to open the file and check.

The best answers were from those who suggested the formula of multiplying the pixel count by 3. That comes pretty close to the figure in Photoshop.

Thanks for the comments. I can now close this.

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