JPEG similar size to RAW

[Steve Greenway]

Hi,

I am sure this topic has been raised before, but I would like ot be able to create full size 100% quality JPEGs from my edited RAW (CR2) files.
I am expecting my JPEGs to be a lot smaller than my original RAW files, but they aren't. For example a CR2 file is 29.6MB and after editing etc, I exported to 100% quality JPEG using the default settings and the resulting JPEG is 20.7MB.

I was expecting the JPEG to be in the region of 5-7MB in size, and suitable for printing full size.

Is this "normal" or am i doing something wrong?

[TomV]

You did not do any thing wrong. You selected the best JPEG setting and got a large file as a result. Try setting to something like 75% and the size will drop dramatically.

[Emil]

Also, even RAWs may be compressed lossless or lossy. IMHO there's no relation between file size and image quality.

[Framon]

It seems that the compression ratio when switching from a processed RAW image to JPG format varies from one software to another. The one I use reduces the size more than ACDSee, but still maintains the best JPG quality.
But I have no explanation for this...

[Steve Greenway]

Thanks for these replies.
I am trying to keep the file size as small as possible as it takes up a lot of my allowance, but they still need to be of a high enough quality to be printed at full size.

So if anyone has any great suggestions, I'm open to options.

[Framon]

Yes, of course, everyone tries to save disk space but let's stay calm, a disk of 2 Tb, a usual standard, can still contain more than 80 000 JPG photos in high resolution...

[Greyfox]

Steve Greenway

Perhaps one should differentiate between "quality" and "resolution", and also consider requirements for specific end purpose images separate to that for long term storage..

There are many on line articles that provide guidance as to what resolution should be used for different print or display tasks.
For example see https://www.optimalprint.com.au/resolution-guide

If for a particular end use you want a 10" x 10" print with a print resolution of 400 dpi, then the pixel size of the image would need to be 4000 px by 4000 px. For a 24 bit RGB image, that would give an uncompressed image size in the order of 48 MB. Sometimes the end use might dictate saving that image using a specific file format, at other times you may be able to consider the merits of other formats available to you.

In terms of quality though, resolution is only part of the picture. Obviously camera settings at the time the photo was taken, correct focus, good lighting, composition etc all contribute to the quality of the photo, but also so do some of the post processing decisions. For instance 24 bit color depth (which is the limit for JPG images) will sometimes not show color gradients as well as 48 bit does, so exporting an image produced from a 48 bit RAW image in a format that reduces the color bit depth to 24 can potentially reduce the quality of the viewed image. Retaining 48 bit color depth on the other hand means a larger uncompressed image size (around 96MB for the 4000px by 4000 px image).

There is also the export format itself to consider. Whilst JPG can offer significant compression, it is a "lossy" format, so some quality in comparison to the original is lost each time an export to JPG is made..Depending on the level of compression, that might not be an issue for the end purpose.. JPG compression can also introduce artifacts, again reducing image quality.

There are of course other formats one can use. HEIF (High Efficiency Image File Format) is said to provide better compression than JPG and can handle both 24 and 48 bit color depth. It may eventually replace JPG, but support for it at the moment is still limited, and until such time as ACDSee can save files in that format, it is not really an option for ACDSee users.

Within ACDSee's current export options, the TIFF format provides the choice of uncompressed or "lossless" compression. ACDSee also provides a number of different compression algorithms for TIFF, perhaps the most common being LZW, and TIFF files can be exported in either 24 or 48 bit color depth. The PNG format also supports "lossless" data compression, however as far as I am aware, while ACDSee can read both 24 and 48 bit PNG images, it can only export PNGs as 24 bit. (I stand to be corrected on that as it's not a format I personally use much). Both of these formats however will produce larger files than JPG.

As you appear to be starting with RAW images, any post processing that reduces the color depth, reduces the resolution, or involves an export using a lossy compression format is going to degrade the quality to some extent in comparison to the original. That can of course still be both acceptable and at times necessary for specific end use images..

What ever you decide to use for a particular end task though, my advice is to always retain your source images in their original format. If you retain the originals, you can always produce different end use copies from them, but you can't ever get back that which has been thrown away.

File storage these days is relatively cheap. A 2TB NTFS formatted drive has a usable storage capacity of around 1863 GB, which should provide storage capacity for at least 60,000 30MB raw images with their associated xmp sidecar files. New Seagate 2TB USB3 Expansion Drives are currently available here in Australia for $AUD 55.20 each, which for 60,000 images gives a cost per image in the order of only 0.092 of a cent (or around 4,300 images for the cost of a cup of coffee)

My 2 cents worth..

[Framon]

Your analysis is correct, Greyfox. You are absolutely right. I was not precise in my message.

As far as I'm concerned, when exporting to JPG using the development software I use (which is not ACDSee), I set the resolution to 300 dpi and maximum quality. My photo prints do not exceed 60 cm x 30 cm (24 " x 12 "). I am fully satisfied with the results and yet, I am quite demanding.
Of course the export in TIFF does not suffer from a loss of quality like the JPG but the laboratories rarely accept this format.
I am not sure that one would see a big difference when printing in these dimensions. Maybe you have a better experience than me. If so, thank you in advance for informing me.

Thanks again for your explanations and your availability to answer questions.

[Reeka]

"Thanks again for your explanations and your availability to answer questions."

+1 Agree. Seconded. You got that right !!!

[Greyfox]

..Of course the export in TIFF does not suffer from a loss of quality like the JPG but the laboratories rarely accept this format.

I haven't had any problem locally with pro print laboratories accepting TIFF images, but I'm not sure whether self serve photo kiosks can handle them.

I was actually in touch with a local pro print laboratory just today, enquiring about getting a 14" x 11" photo printed to go in a 16" x 20" frame.
When I asked what their preferred image format would be for that application, I was asked what the original ex camera format was. When I said it was RAW image, they suggested TIFF, 16 bit per channel, with Adobe RGB 1998 color profile.

[Framon]

Thank you very much for this interesting information. It is true that, until now, I dealt with an online laboratory.
I'm going to inquire in my region when I return from a trip at the end of this month.
Do you know if this kind of laboratory also perform the confection of bound photo albums?

[Greyfox]

..Do you know if this kind of laboratory also perform the confection of bound photo albums?

Not the one I communicated with today.

[Framon]

OK. Even if your lab did it, it would still be a bit far from my home. I live in Belgium... ;-)