Export options

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Level 1

6 points

Export options

Hello Guys,

Hope you are good! I want to ask you two questions today. I'm trying to export some of my photos library. When you choose File -> Export from the menu it gives two options: Export Photos and some formats (jpg / png etc) and Export Unmodified Originals... Is there any difference between the photo quality (if i export it with a format or unmodified) of the photos or is the same?

Also one more question. What depth has the PNG exporting file in Photos App? I mean, the exported as a png file is an 8 bit file or a 24/32 bit file? I tested a PNG-file in Affinity photo App and it says RGB/8, so I think it's a 24/32 bit file, but I'm not sure!

Thanks in advance!

Leo

Posted on Apr 16, 2018 11:57 PM

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Answer 1

léonie

Level 10

200,645 points

Apr 17, 2018 4:52 AM in response to leoskats

Is there any difference between the photo quality (if i export it with a format or unmodified) of the photos or is the same?

Yes, there is a difference.

If you export. with "unmodified Original", Photos will save a copy of the original image, exactly as you imported it. There will be no adjustments applied. It will give you the same quality as the original image has.
If you export with "File > Export > Export .. photos", Photos will render a new image file from the original with all adjustments you applied. It will depend on the settings you select in the export dialog, what the pixel size of the photo and the quality will be. You will get the best possible quality, if you select "TIFF 16 Bit and and Full Size". This will create unnecessary huge files, if the original image has been a JPEG.

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Answer 2

leoskats Author

Level 1

6 points

Apr 18, 2018 2:51 AM in response to léonie

I had read in one forum that in order to find out if you had an 8-bit PNG or a 24-bit PNG you have to "open both photos in Photoshop.Then you check what's written on the top bar. If it says "index", then it has been saved as 8-bit PNG, if it says "RGB/8" then your PNG is a 32-bit one." I have found that Photos App exports RGB/8 photos, so if you export a png file format it's an 24-bit PNG one.

Personally I use a 24-bit PNG file for my photos, because it's like a JPG one but with no loss in quality. 24-bit PNG photo files have a wide palette, that consists of more than a million colours and the result is the same with JPG but in a crystal image quality. The 8-bit PNG, supports only 256 colours and it's special for graphics, not for photos.

I try to work, as you said, with TIFF. I saw that has RGB/16 bit and thus extraordinary quality, but when I try to upload or to work in web with it, the result comes with problems and error. I don't know If I make a mistake?! So for now I use a 24-bit PNG that it's uncompressed and lossless, like TIFF, and I can upload those files perfectly in web! If you know other alternative, feel free to reply 🙂

Thanks in adance,

Leo

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Answer 3

LarryHN

Level 10

106,142 points

Apr 17, 2018 4:27 PM in response to leoskats

JPEG is a lossy format and depending on the JPEG parameters you choose has more or less loss - TIFF is a lossless format so by definition is better than any JPEG file - a good quality JPEG may well be good enough for your needs, only you can determine that but a TIFF will always be the same quality as the original and a JPEG will always be a lower quality than the original in absolute terms -- most people happily use medium to high quality JPEGs

Again what you use is your personal decision - there is no answer to which to use except to use the one that meets your needs

LN

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Answer 4

leoskats Author

Level 1

6 points

Apr 17, 2018 2:18 PM in response to léonie

Hello Léonie,

Thanks for your reply. Okay I see your tactic. But can I ask you something? What's the difference from the PNG-24? TIFF has great quality too, but the huge size make it inaccessible on Facebook and Instagram. For example, I can't upload one TIFF file photo in Facebook and Instagram supports only JPG / JPEG and PNG.

Moreover I make a comparison between the two files (TIFF and PNG) and I can not see any haze or lower quality. Both files produce a crystal image. Do they eventually differ only in size and do the same photo result? Do you have a comparison of your own?

Thanks again!

Leo

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Answer 5

léonie

Level 10

200,645 points

Apr 18, 2018 3:31 AM in response to leoskats

I don't know If I make a mistake?!

It really will depend on the way the photo will be used on the web page. If you just want the photo to look good on the page, but the photo is not meant to be downloaded by others, lossless is not that important. You only need a lossless format, if you want to print a photo at high resolution or to edit it further.

If a photo will not be enlarged beyond what will be displayed on the webpage, it it more important that the file size is small and the page will load quickly.

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Answer 6

léonie

Level 10

200,645 points

Apr 17, 2018 11:33 PM in response to leoskats

Apple did not document in the Photos Help, which PNG version will be used when exporting from Photos. You have to find out by experimenting, like you did by opening the photo in Affinity. A PNG file can either be a lossless RGB bitmap, like a TIFF or a palette with a reduced color table, like a GIF. All PNGs I exported from Photos have been exported as 8-bit RGB files, uncompressed, even when I exported a 16-bit TIFF image as a PNG. The PNG files are much larger than the original JPEG.

Personally, when sharing to a web site, I would use PNG files only for graphics, were a limited set of colors is needed. Then a PNG will give much better results than a JPEG. And I would use a JPEG to show a photo on a web page. A JPEG will allow you to compress the image slightly and reduce the amount of network traffic for the upload and download to the site.

It is great, that Photos allows us to save photos as 16-bit TIFFs, but that is not feasible for archiving purposes. I am using it, when I want to send a photo losslessly to an external editor. It makes only sense, if the original RAW file has more than 8 bit color resolution. The file size of 16-bit TIFFs, uncompressed is ridiculously high. I just saves a HEIC file taken with my iPhone and with a file size of 1.6MB as a 16-bit TIFF and the exported file has a size of 78MB:

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