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38MB Nighttime/Skyline RAW Image Saves as 14MB JPG?


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Hi,

 

I recently began shooting nighttime skyline RAW images, but I noticed that I'm lucky if my final edited JPG image is more than 17 MB.  The nighttime RAW image will be about 35-40MB, with the exported LR image at 13-14 MB, and then the final edited image at around 14-18 MB in size. 

 

I tried exporting from Lightroom to PS as original, DNG, TIFF, and JPG, but I'm still dealing with Photoshop automatically discarding about 60% of the image information.

 

I understand that less light and color equals "smaller" images, but does anyone have any secrets they're willing to disclose to preserve image size when saving to JPG (over the current "Baseline Optimized" and "Image Options" settings).

 

Frank

 

P.S.  I completely understand and appreciate why Alamy is so discriminating with submitted images. Today is Friday Oct 7 and take a look at the featured image on Bing.com. It's a great shot by the photographer, but look at the grain that was accepted by Getty! And I've noticed this level of acceptance coming from Getty in the past as well.

 

 

 

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are you talking about file size as in the size of the file stored on disk or are you talking about the size of the image when opened in an image program, i.e., memory size?  it's the latter that matters.

 

17mb is an (8-bit) image with a dimension of roughly 3000x2000 pixels; so as long as your final jpg is 3000x2000 or bigger, then it will meet alamy minimum of 17mb.   note that raw files may be bigger in memory as they may be  12, or 14, or 16 bit. 

 

raw, tiff, jpg, dng, etc. they all compress the image in different ways and their file sizes on disk will differ. but in memory (as an 8-bit image) they are all the same size.

Edited by sooth
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Hi Frank,

Your exported edited JPEG size at 14-18MB is perfectly fine, don't worry about it. As long as you're exporting as quality 100 under 'file settings' under export, it's all good.

 

Re. your p.s., yes Alamy has higher technical requirements than other agencies, although in my view, they're still too lenient on the quality of some of what they let through.

Steve

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Its not PS that's 'discarding' the data.

Converting to a JPEG goes through 'lossy compression' which means you can get smaller file sizes without any 'appreciable loss' (depends on how aggressive you want the compression to be) in image quality.

The image size in pixels will be the same as your original RAW file but on disk will appear to be a lot smaller i.e 35Mb for the RAW and 17Mb for the JPEG

 

To be honest don't worry about it, its all good. Camera, PS, LR are all doing the right thing and as Steve says as long as quality for JPEG export is 95-100% then there will be no issue.

I suggest worrying about captioning, keywording, taking pics that sell etc

 

 

 

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Also on your PS. about grain etc.

There is some artistic license allowed at Alamy as long as it is enhancing the spirit of the image and not just an obvious technical issue.

 

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Thanks much for the replies. Yeah, I was concerned/confused because Alamy states they "need a file size of over 17MB when uncompressed (this is likely to have a compressed JPEG size of 3-5MB)." But then I'm reading a lot in the forums that the images must be at least 17MB in size.

 

Since we're all submitting compressed JPG's, then based on what Almy states, we can actually submit a final edited JPG image that can be 3 or 5MB in size.  And that 3-5MB size would be accepted, providing all other criteria are met; submitting good clean noise-free and tack sharp images that perhaps began at 35-40MB in RAW.

 

Sorry for my confusion, but my dyslexia can be a pain in my arse.

 

Frank

 

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3 hours ago, frankbiganski said:

but I'm still dealing with Photoshop automatically discarding about 60% of the image information

Clearly that statement is incorrect so I'm wondering what made you think that is happening.  I see that you have taken the forum's advice and uploaded 3 'safe' images for your successful initial submission. You'll see that Alamy display their 'File size', their 'Compressed download size' and their pixel dimensions. The 'File size' is the uncompressed file size and the 'Compressed download size' is the size on disc of the jpeg.  So for your 3 images we have:

 

2JWM521  - 4928 x 3264 px - 46MB - 4.4 MB

2JWM543 - 7362 x 4912 px - 103.4 MB - 5.5 MB

2JWM523 - 7362 x 4912 px - 103.4 MB - 5.4 MB

 

The File size is just maths which Photoshop does for you, so for your Nikon D810:

7362 x 5912 = 36162144 which divided by 1000000 gives you the sensor size in Megapixels (MP) = 36.1MP

but....

For an RGB image you need to multiply this figure by 3 to get the theoretical file size in bytes, but a Megabyte is 1024 x 1024 bytes, so you divide the total by that

...and the answer is 103.46 MB and this would loosely equate to the size of an 8-bit tiff of that image.

 

Back to the jpegs, the 'Compressed file size' is the size of the jpeg that will be delivered to the client, i.e. after the jpeg you uploaded has been compressed again by the Alamy upload system. It would be interesting to know how big your jpegs were for these 3 images. Personally I think that 13-14 MB jpegs for nighttime skylines is pretty high given that you would expect there to be large areas without significant detail.

 

 

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Oh crap, math! I used "Frank math" (35MB - 60% = 14MB). Math at nearly any level is my disability but, what you provided will help me get a better grasp on how this works. And I appreciate that. I need to explore how you found this file information too.

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9 minutes ago, frankbiganski said:

Oh crap, math! I used "Frank math" (35MB - 60% = 14MB). Math at nearly any level is my disability but, what you provided will help me get a better grasp on how this works. And I appreciate that. I need to explore how you found this file information too.

 

Frank, I appreciate Harry's maths, but I wouldn't worry about learning it. You now know that what you're doing is ok in terms of file size. The file size stuff is really only for reading up on when you're bored or it's a really rainy day. 🙃 I would follow Martin's advice next:

 

2 hours ago, Martin L said:

I suggest worrying about captioning, keywording, taking pics that sell etc

 

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29 minutes ago, Harry Harrison said:

2JWM521  - 4928 x 3264 px - 46MB - 4.4 MB

2JWM543 - 7362 x 4912 px - 103.4 MB - 5.5 MB

I found the image information you're referring too.

 

Strange thing is, I uploaded image 2JWM521 to Alamy as a 22.5MB JPG, so how did it turn into 46MB?  And image 2JWM543 was uploaded as a 30.6MB JPG image, yet Alamy states 103.4MB.

 

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18 minutes ago, frankbiganski said:

I need to explore how you found this file information too.

It's displayed under the images in the 'zoom' view. It's possible I suppose that if your nighttime skyscapes have graduated skies and fine detail in the buildings then high quality jpeg compressed images might be quite large, your 'safe' images have a lot of blue sky so will tend to be smaller. Jpeg compression works by comparing neighbouring pixels so large areas of even tone and colour can be compressed very well. In Photoshop you can create a layer 'cake' of the same image saved at different levels of compression/quality, it can be quite illuminating just comparing different layers visually (switching them on and off) or more scientifically by letting Photoshop compare the difference.

Edited by Harry Harrison
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3 minutes ago, Steve F said:

You now know that what you're doing is ok in terms of file size

Well in fact he didn't know (14MB / 35MB = 60% loss) , it's always good to understand stuff, I'm not suggesting that he, or anyone, calculates it.

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3 minutes ago, Harry Harrison said:

Well in fact he didn't know (14MB / 35MB = 60% loss) , it's always good to understand stuff, I'm not suggesting that he, or anyone, calculates it.

 

I meant the file sizes Frank is submitting to Alamy are fine.

 

p.s. Harry maths is too complicated for Friday afternoon 😆

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10 minutes ago, frankbiganski said:

Strange thing is, I uploaded image 2JWM521 to Alamy as a 22.5MB JPG, so how did it turn into 46MB?  And image 2JWM543 was uploaded as a 30.6MB JPG image, yet Alamy states 103.4MB.

Frank, I appreciate that your dyslexia might be getting in the way here, but a better question to ask is how your 22.5 MB jpeg ended up as only 4.4 MB. The '46MB' is the theoretical size when opened in Photoshop, the notional 'uncompressed file size'.

Edited by Harry Harrison
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28 minutes ago, Harry Harrison said:

But Frank doesn't know why they are fine. 

 

That's exactly it, and I'm popping one open now (working on my own stuff at home, so it's safe). Had a long work week too. 

 

But this is enough info for me to work with, and I found a long thread you guys were involved in from 2019 that went into this and a lot more. Late afternoon reading. I'll move it forward and I'm good with your answers.  I'm getting together a half-dozen images to upload and that's when I saw some of my images were 13-14 MB in size and I freaked.

 

Thanks gents!  Much appreciated! 🍻

 

 

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19 minutes ago, frankbiganski said:

I'm getting together a half-dozen images to upload and that's when I saw some of my images were 13-14 MB in size and I freaked.

Even if you don't do the layer cake thing it's quite instructive to save jpegs from RAW at different quality levels and see what (actual) file sizes you get. As Martin says it's OK to upload at a little less than 100% quality and that can make a huge difference in jpeg (on your disc) file size with no discernible difference in quality. I'm actually pretty surprised that your 22.5MB jpeg was processed down to 4.4MB by Alamy, and even more so that your 30.6 MB jpeg went down to 5.5 MB. A 30.6 MB jpeg sounds very large?

Edited by Harry Harrison
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Frank has Photoshop so there is no math(s) required as long as he can read numbers. To keep things really simple, export as JPEG from Lightroom (ensuring image is 8 bit), open the image in Photoshop, hit Image- Image Size and a dialog box will appear with the Image Size shown at the top. As long as that number is at least 17 he is good to go. He need not bother his tired brain with calculations. 

 

 

6 hours ago, frankbiganski said:

.Today is Friday Oct 7 and take a look at the featured image on Bing.com. It's a great shot by the photographer, but look at the grain that was accepted by Getty! And I've noticed this level of acceptance coming from Getty in the past as well.

 

 

That is digital NOISE not grain and it is pretty horrendous. The distinction is important. 

Edited by MDM
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37 minutes ago, MDM said:

To keep things really simple, export as JPEG from Lightroom

Do you think that Frank's 22.5 & 30 MB jpegs from a D810 are typical? Very surprised at the size they end up on Alamy if so.

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15 minutes ago, Harry Harrison said:

Do you think that Frank's 22.5 & 30 MB jpegs from a D810 are typical? Very surprised at the size they end up on Alamy if so.

 

That is not unusual at all. It depends on the content of the image. If there is a lot of detail they can easily hit 30MB or more on disk. JPEG files from 45MP cameras could be a lot larger again. 

 

There were a few discussions about maxiumum disk files sizes on a few months ago with people getting images above 25MB auto blocked on upload. I never had a problem in the past but I think I had a test one blocked using Safari but it went through with Firefox. I didn't mention file sizes on disk to keep it very simple. 

Edited by MDM
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7 hours ago, frankbiganski said:

Since we're all submitting compressed JPG's, then based on what Almy states, we can actually submit a final edited JPG image that can be 3 or 5MB in size.  And that 3-5MB size would be accepted, providing all other criteria are met; submitting good clean noise-free and tack sharp images that perhaps began at 35-40MB in RAW.

 

no. don't go by compressed file size.  open your image in photoshop or other editor and look at the UNcompressed file size, i.e.,, memory size, again, that's what alamy is looking for.  

 

 

 

6 hours ago, frankbiganski said:

I found the image information you're referring too.

 

Strange thing is, I uploaded image 2JWM521 to Alamy as a 22.5MB JPG, so how did it turn into 46MB?  And image 2JWM543 was uploaded as a 30.6MB JPG image, yet Alamy states 103.4MB.

 

 

it didn't.  the 22.5MB is your compressed file size, the 46MB is the uncompressed file size when you open it; alamy wants uncompressed.  don't worry about what the file size is on the disk, it's irrelevent.  As long as your image is at least 3000x2000, then you met alamy's 17mb uncompressed image standard.   

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