PDA

View Full Version : Does pushing the processing affect file size?



Luna-blu
10-09-2011, 8:50am
So I know that editing and resaving a jpg will reduce the quallity and file size, but this was all done on RAW's in lightroom so I know that's not the problem.
The photos were quite underexposed and so had a to be pushed a fair bit in LR to bring the exposure up then exported the JPG at highest quality no size reduction.

I did an export using the same settings on the unedited RAW's and the difference in file size is around 6mb.

I think I'm sure that the more you push the processing the more you'll degrade IQ and consequently file size, but then I've been known to be wrong on occasions too (80's hair for example) so is anyone willing to shed some light for me? I"d really appreciate it!

Cheers!

ricktas
10-09-2011, 8:54am
Yes it can.

Take a photo and save it in colour, take the same photo, convert it to mono and save it, using the exact same save settings (quality, etc)
. Check the filesizes.

JPG is a LOSSY format, meaning each time you re-save it, you lose data as the JPG format compresses the file. JPG was developed to save filesize and space, early on in the internet, when download speeds were slow etc.

RAW, TIF, PSD and others are NON Lossy, meaning they do not lose data due to compression

Luna-blu
10-09-2011, 8:58am
Thanks Rick, I thought I was on the right track but I wanted to be sure.
Sorry I havn't been very active lately I've been busy banging my head against a brick wall!

WhoDo
10-09-2011, 9:03am
In short, Yes! All additional information in the image will increase it's size, both compressed and in RAM. That is especially true with non-lossy compression formats, but still holds even for JPEGs which are a lossy format (image data is lost in compression algorithm). Adding contrast involves making image points different to those around, for example, so extra image data is created. I hope that helps.

Luna-blu
10-09-2011, 9:07am
Sorry the processed files are smaller not larger, that helps.

Kym
10-09-2011, 9:22am
Yes, but the result maybe either smaller or larger - just depends

WhoDo
10-09-2011, 9:26am
Sorry the processed files are smaller not larger, that helps.
As Kym says, it can be either way depending on what processing you've done. Different processes will add or remove image data and sometimes the net effect can even be virtually zero. Try each process on an original and note the resulting size to see which ones have which result. You might be surprised! ;)

Luna-blu
10-09-2011, 9:31am
As Kym says, it can be either way depending on what processing you've done. Different processes will add or remove image data and sometimes the net effect can even be virtually zero. Try each process on an original and note the resulting size to see which ones have which result. You might be surprised! ;)

Good idea! I'm gonna try that now and see what happens, bit dissappointed that I didn't think of doing this sooner though :o

WhoDo
10-09-2011, 9:41am
Make sure your JPEG conversion is at 100% and best quality to take the bulk of the compression algorithm out of play. I'd be interested in your results, too. :th3:

Luna-blu
10-09-2011, 10:08am
I always double check my export settings and set them to the highest quality.

Original processed file - 6.77mb

Unprocessed - 10.6mb

Exposure +2.12 - 15.9mb

Black Clipping -1 - 15.6mb

Brightness +15 - 15.8mb

White balance - 15.9mb

I think I now know whats going on, I edited these for a "fauxtographer" and I think my original files have been fiddled with, it's the only way I can see that the original export could now be so low compared with the results of todays exports.

yummymummy
10-09-2011, 9:37pm
oh good lord is she STILL on your case :( I'm sorry she's being such a cow :( *hugs*

Luna-blu
11-09-2011, 2:00pm
I haven't spoken to her yet, she won't take my calls.

Thanks for the advice everyone, I have learnt a good lesson through this experience and I doubt I'll make the same mistake twice.

arthurking83
11-09-2011, 3:30pm
..... I think my original files have been fiddled with, it's the only way I can see that the original export could now be so low compared with the results of todays exports.

I'm not 100% sure I understand this part :confused013

You said that the original files were raw??

When using LR, the size of the raw file should change irrespective of the edits made. One thing I'm lead to believe about Adobe software is that it never handles the raw file directly, and only saves all it's edits into a separate file. This (LR generated)file needs to be sent to you as well if you are to see the edits that the fauxtog made to any raw files.. otherwise they've sent you jpg files.

That is, if the fauxtog captured the images in camera as raws, and sent you the raw files, unless they sent you two files the fauxtog can make any adjustments to the raws, and you would be none the wiser.
Without the LR generated separate side car files for each raw, the raw files are viewed by you in the raw so to speak.

If you then subsequently edit the raw files and the fauxtog wants them all back in the edited state, you also need to send to them the LR generated files that contain the edit info, otherwise they have the exact same raw files as they sent you.

In your list, what file types are these files? Are they all the jpg'ed export files?
That is, this 'original unprocessed' file is 6.77Mb. Is that a jpg file that the fauxtog sent you as well as the raw file? If so, it's probably smaller due to a level of compression, or a different algorithm used by a slightly different software setup .. etc, etc.

Luna-blu
11-09-2011, 5:48pm
Yup, the above figures are for JPG's, and as far as I know the the lightroom adjustments are stored in the catalog and/or the .xmp files.

I got them on a hard drive as raw's, setup a seperate catalog for them within the main file, imported, edited then exported JPG's at highest quality using a preset and gave her the drive back.
The 'tog then emailed saying that the image files were too small and pixellated when printed.
I checked the last time they were accessed on windows expolorer and it looks like they've been opened and resaved after I gave the drive back.
It was the original jpg exports that I think she's fiddled with, it's the only explanation I can come up with now.

I thought maybe it was because the exposure was pushed so much in post, and willing to concede that it may have been something I'd done but I just can't see how.

However if anyone can see something I have done wrong let me know, I'm always up for a bit of personal development.

WhoDo
11-09-2011, 6:03pm
I got them on a hard drive as raw's, setup a seperate catalog for them within the main file, imported, edited then exported JPG's at highest quality using a preset and gave her the drive back.
The 'tog then emailed saying that the image files were too small and pixellated when printed.
I checked the last time they were accessed on windows expolorer and it looks like they've been opened and resaved after I gave the drive back.
It was the original jpg exports that I think she's fiddled with, it's the only explanation I can come up with now.

I thought maybe it was because the exposure was pushed so much in post, and willing to concede that it may have been something I'd done but I just can't see how.

However if anyone can see something I have done wrong let me know, I'm always up for a bit of personal development.
The only thing I can suggest is that when saving from RAW to JPG, not only do you need to set the Quality at 100% and Best, but you also need to check your software isn't processing at a default 72dpi for the web.

When preparing files for printing it is important that the dpi for the exported JPG is not less than 150 and preferably 300 to prevent pixelation on printing at larger sizes. That could also account for such a dramatic difference in size between the original RAW file and the exported JPG. Just a thought and not suggesting that's what happened. :confused013

arthurking83
11-09-2011, 6:24pm
.....

I got them on a hard drive as raw's, setup a seperate catalog for them within the main file, imported, edited then exported JPG's at highest quality using a preset and gave her the drive back.
The 'tog then emailed saying that the image files were too small and pixellated when printed.
I checked the last time they were accessed on windows expolorer and it looks like they've been opened and resaved after I gave the drive back.
......

From this, I reckon you're 99.99999% in the clear and that the fauxtog has fumbled her way through the images and stuffed something up.



.. However if anyone can see something I have done wrong let me know, I'm always up for a bit of personal development.

You've allowed her write access! Bad move, now you know better. 'personal development' session now over! :D

Did you make any backups to any of your drives?

I'd say that the best approach now is to email her back and explain that there will be another fee to reprocess the images back to the original size that you saved them at ;)

(is she worth the hassle? if not tell her to do them herself. Some people are not worth the time and effort, and best left to their own devices)

Also, because of this thread, i just went in to look at the contents of my LR catalogue and deleted it all.
Entire LR file cache was in the order of only 38Mb or so, but having deleted every single bit of info available to LR in there has done wonders for the speed of the software!
Note that I don't use LR for any important editing, and in fact rue the day I got it now, as waste of money. but I made my choice and will persevere with it 'for testing purposes' only.. no really serious editing.
So to delete the entire catalogue is not an issue. Just an interesting observation.
One other thing, I couldn't find tho are these so called .xmp files. In the Lighroom folder in the My Pictures folder is a catalogue directory and there are numerous other folders with the .lrprev files for what I assume is every image LR has edited, but I see no .xmp files.

arthurking83
11-09-2011, 6:48pm
The only thing I can suggest is that when saving from RAW to JPG, not only do you need to set the Quality at 100% and Best, but you also need to check your software isn't processing at a default 72dpi for the web.

When preparing files for printing it is important that the dpi for the exported JPG is not less than 150 and preferably 300 to prevent pixelation on printing at larger sizes. That could also account for such a dramatic difference in size between the original RAW file and the exported JPG. Just a thought and not suggesting that's what happened. :confused013

This is only true if you've set the export process to resize the image. If LunaBlu hasn't set the export process to resize the images, the x,y pixel count will remain the same as the raw file. Whatever the setting in the ppi box is basically disregarded (I think.. well it should be if there is no file resizing going on!)

LunaBlu then says that the the fauxtog is claiming that the jpg files are too small. A change in ppi values doesn't really affect pixel numbers, but only how the printer is going to interpret the image and set itself up for printing the file to an image.

What are the actual pixel dimension values of the image itself? Not just the file size, the actual pixel size of the 6.77 Mb image? Is it different to the 10Mb version. ie has she resized them into a smaller file?

Is the Phauxtog printing them from home on her inkjet printer, or via a professional or even consumer level lab?

From my understanding, a 6Mb jpg file is pretty good file size for a 20 or 30 inch print according to the info I've got from my favoured pro lab. As long as the image has good detail to begin with, there should be no problem in printing large. How large is she wanting to print? If at home, surely it can't be more than A3!

FWIW: if an image needs 2.12Ev of exposure compensation to make a print, the fauxtog should be concentrating more on her (in)ability anyhow!

Luna-blu
11-09-2011, 7:05pm
I always export at 300dpi for jpg, although I understand and am grateful for the advice nonetheless. I've never been arrogant enough to believe I'm a VIP (very important photographer) :Dx

The pixel dimensions are the same as the original raw, I straighten them and thats the only crop they get. but fyi it's 5184 x 3456



One other thing, I couldn't find tho are these so called .xmp files. In the Lighroom folder in the My Pictures folder is a catalogue directory and there are numerous other folders with the .lrprev files for what I assume is every image LR has edited, but I see no .xmp files.

Lr will store in catalog and .xmp but you have to have the .xmp turned on, I prefer to leave it unchecked, dunno why just do?
Edit - preferences - general - go to catalog settings -metadata - automatically write changes into .xmp

Could you clarify "write access" for me? sounds like something I need to know about.

And a rundown on the tog, prefers to shoot jpg cos doesn't like the colour of raw, edits jpgs, is cranky that I've added "grain" to their underexposed photos, shiddy that the colour is pink when I've done a colourchecker profile for them and informs me (in a most condescending fashion) that shooting in manual is unrealistic when you do a wedding! :umm:

So yes a personal development session indeed! It's giving me a drinking problem!
No they're not worth the hassle, the way I figure is if the fauxtog wants to shoot auto everything and get the irrits that my editing can't fix it all then I have no time for them.
I'd much rather be taking and editing my own photos and hanging out here where I'll be pushed to be a better photographer :efelant:

WhoDo
11-09-2011, 9:07pm
This is only true if you've set the export process to resize the image. If LunaBlu hasn't set the export process to resize the images, the x,y pixel count will remain the same as the raw file. Whatever the setting in the ppi box is basically disregarded (I think.. well it should be if there is no file resizing going on!)
The OP is using a preset to export Arthur, and that could be doing anything, but I accept that the preset is configured for 300dpi as the OP mentions in reply. My software exports for web at 72dpi by default, and I have to be very careful to make sure I reset to print dpi when planning to actually produce hard copy or the resulting image can't be resized much without pixelation. That's also why I don't watermark my web images any more. I don't post them at print dpi resolutions anyway. :confused013

arthurking83
11-09-2011, 9:44pm
Sorry Luna the jibe about allowing her write access to the files was a bit of a jab at her. You can write protect the files and she can't alter them. But I don't think this setting is upheld across different computers. never tried it actually. But it was meant a a (bad) joke.

Sorry about my understanding of 'preset' Export routine. I thought that when the mention of Preset is made that this refers to a user defined Preset(as we do in our software). There are no pre defined prests in saving in batches, the user defines everything and saves it as a preset .. sorry!

Luna-blu
11-09-2011, 9:59pm
It's all good, you gonna have to work a lot harder if you want to offend me!
No it's a my own preset, I was just so confused as to what was going on and didn't want to be arrogantly igonrant, but thanks to Whodo's advice on exporting at each step it set me on the track of investigating someone else.
I don't think I'm the latest and greatest, but at the same time it's reassuring that I have good file handling systems.

You guys are the best, don't ever change

soulman
11-09-2011, 11:24pm
My software exports for web at 72dpi by default, and I have to be very careful to make sure I reset to print dpi when planning to actually produce hard copy or the resulting image can't be resized much without pixelation.Arthur is correct - the DPI has no effect on quality when you're saving/exporting: a 3000 X 2000 pixel image will print exactly the same whether it is set to 72DPI or 1200DPI on export. The only thing that will make your web exports pixelated is being reduced in pixel dimensions.

WhoDo
12-09-2011, 6:11am
Arthur is correct - the DPI has no effect on quality when you're saving/exporting: a 3000 X 2000 pixel image will print exactly the same whether it is set to 72DPI or 1200DPI on export. The only thing that will make your web exports pixelated is being reduced in pixel dimensions.
Interesting comment. We are not talking about web exporting but PRINTING and dpi setting WILL impact on that with lower dpi resulting in pixellation when the image is upsized for larger prints. One of the complaints to the OP from the client was of pixellation on upsizing for printing.

soulman
12-09-2011, 5:18pm
We are not talking about web exporting but PRINTING... You were talking about exporting image files in the post I responded to.

The important thing for the OP, as far as this part of the issue goes at least, is that setting DPI when saving a file has no effect on file size or image quality. It's just a reference for other software to use for calculating how large a print could be made if it were to be made at that resolution. Print resolution is set at the time of printing - by your client in this case, so outside your control - and will override whatever is in the EXIF.

In terms of trying to move toward resolving the original issue, you can only guarantee the images you deliver, so if the images your client is having trouble with have been re-saved then they are no longer what you delivered and not your responsibility. This is not easy to get across if the person is not being rational. Good luck.

WhoDo
12-09-2011, 6:10pm
The 'tog then emailed saying that the image files were too small and pixellated when printed.


You were talking about exporting image files in the post I responded to.

I was responding to the fauxtog's complaint quoted above and offered the only explanation I could think of for the whole circumstances complained of, not just the assumption on the part of the fauxtog that file size was linked to pixellation .

You are correct that the file size doesn't change regardless of the dpi setting when exported. OTOH, as soon as you try to resize for printing, the 72dpi image will pixellate at larger sizes where the 300dpi may not ... depending upon how large a print you are after of course. I would NEVER try to upsize a 72dpi image for printing on, say, a large canvas regardless of the original pixel resolution.

Your claim that "a 3000 X 2000 pixel image will print exactly the same whether it is set to 72DPI or 1200DPI on export" is simply incorrect, Trying to print in a larger than native pixel size at 72 dpi = pixellation. That is what lead to my response to the OP about the dpi of the exported image. :rolleyes:

Luna-blu
15-09-2011, 9:40pm
Well thankyou all very much for your help and suggestions, as always you were most kind and generous.
The fauxtographer is now willing to accept some responsibility for what has happened, which is nice.
But I think I've learned more from this than they have, onwards and upwards for me!