need help with jpeg compression

[robertj298]

Thanks for looking steve. One big difference I see is your tiff file while yours starts the same as mine when I save mine at 100% quality jpeg it is reduced to 500-600 k. I'll email you the original jpeg I exported from lightroom 1.4 before it crashed...Bob

[steve.ledger]

One big difference I see is your tiff file while yours starts the same as mine when I save mine at 100% quality jpeg it is reduced to 500-600 k. I'll email you the original jpeg I exported from lightroom 1.4 before it crashed...Bob

I'm so confused with understanding your workflow Bob, sorry..

[robertj298]

Oh here is my exact work flow for the last image I emailed you. Imported the raw file into lightroom 1.4from camera. Tweeked the photo in lightroom 1.4. I exported the photo into psp9 as a high quality jpeg to get rid of some dark circles under the eyes. I did that with the smudge brush the saved. I ended up with the 4.68 meg file I emailed you. When I tried to duplicate this using lightroom 2.1 before recovering data from my hard ( I still had the photo on my memory card) I end up with a 700 kb file...Bob

[steve.ledger]

I think this is just a matter of getting ones head around what is happening under the hood..

This is how I understand it.

When you press SAVE in PSP you are using the default save settings for that file type, which is 25% compression / 75% quality.
25% compression setting does not mean the file will be just 25% smaller than the original, it means the file will show 75% of the ‘quality’ of the original file.

So your result of 700KB is really quite normal, I got pretty much the same result too (657KB in fact).

When you Export and use the JPG optimiser (with the compression to the lowest value of '1') - you end up with the 4.7MB JPG, as did I. This too is normal as you are compressing the file using the JPEG algorithm but set to retain 100% of the orginal 'quality' (even though it is still using lossy JPG.)

[robertj298]

Thanks steve your info finally hit me on what I was doing wrong. I thought when I set the jpeg optimizer from the file menu that was used for each photo I didn't realize I had to set it from the window after I click save as also....Bob

[steve.ledger]

No worries Bob, glad we got there in the end

[Trev]

Well to start with you Raw is 16 bits per channel and the Tiff will be also but Jpeg can only be 8 bits so there is a big saving there to start with before you start to compress.

[robertj298]

I think there must be a difference in the compression between lightroom 2.1 which I have now and lightroom 1.4. My files which were exported as jpegs from 1.4 and worked in psp are around 4.5 -5.5 megs. The same files exported from lightroom 2.1 and nothing done to them are about half the size....Bob

[steve.ledger]

I thought we'd sorted this? Obviously not.
Bob there's no compression difference between Lightroom versions when choosing the JPEG export.
Provided you set export options the same, you will get exactly the same result.
I really feel you are getting befuddled somewhere, pity I can't pop over to your and help you out

I just tested LR2 against LR1 with one of my own .PEF RAWs.
I set exposure to 'florescent' and sharpened to 50 then exported at 100 quality level, sRGB 96dpi (exact same process in both versions)
Both files exported to 2.66MB precisely.

Same applies when exporting or saving with PSP, make absolutley certain your save settings are exactly the same as previosuly discussed.

[Trev]

just in case it clears any confusion. Psp uses a different scale. I in Jpeg export is best quality where as 100 is best in adobe and most other programs. Now as for Lightroom 2 against 1 then it must be that the jpeg export slider is set at something different to what you had it set in 1. I believe the out of the box setting is 50%