Lightroom JPEG export VS Photoshop Image Processor

Question

Hey guys:
Long time photoshop and lightroom user (long time user of all things Adobe). First post here in the forums. I did a search for my question but I think it was too specific, so it returned zero results.
My question is about Lightroom's JPEG export vs Photoshops Image Processor. When I export a RAW file to JPEG from Lightroom, the file size is freaking huge. The JPEG is as big as my original RAW file (~25mb). Settings are set to default - 100 quality. Everything else remains untouched.
However, when I use Photoshop's image processor (I launch it through Bridge, easier that way for me) and process the RAW images that way, my JPEGs are roughly 5-10mb in size. Settings in Image Processor are quality 10 and thats it. No actions being run or anything.
Can anyone shed some light as to why Lightroom exports JPEGs that are roughly 2-4 times the size of Photoshop's JPEGs? My initial thoughts are that the 100 quality setting in Lightroom is more like Photoshop's quality 12 (that always makes me think of Spinal Tap - "Why don't you just make ten louder and make ten be the top number and make that a little louder?" "These go to eleven.") Ideally, exporting out of Lightroom would be much easier for my workflow.
Thanks in advance.
-The Doctor

Answer 1

DrMilesBennell wrote:
Can anyone shed some light as to why Lightroom exports JPEGs that are roughly 2-4 times the size of Photoshop's JPEGs? My initial thoughts are that the 100 quality setting in Lightroom is more like Photoshop's quality 12 (that always makes me think of Spinal Tap - "Why don't you just make ten louder and make ten be the top number and make that a little louder?" "These go to eleven.") Ideally, exporting out of Lightroom would be much easier for my workflow.
You are correct: LR Quality 100 = PS Quality 12
Despite LR having 101 Quality settings (0 to 100) it actually only has 12 Quality settings the same as PS 'Baseline Standard':
JPEG Quality Setting Comparison
PS
LR
LR Range
Typical Reduction
0
0
0-7%
11%
1
10
8-15%
23%
2
20
16-23%
14%
3
30
24-30%
14%
4
35
31-38%
16%
5
40
39-46%
24%
6
50
47-53%
4%
7
55
54-61%
27%
8
65
62-69%
25%
9
70
70-76%
31%
10
80
77-84%
35%
11
90
85-92%
41%
12
100
93-100%
I keep a small copy of the above table taped to my monitor. I chose the numbers under the 'LR' column for the 12 steps (not AA's) to make it easier to remember. In actuality ANY number in the LR Range column will produce the same results for each step.
Under the 'Typical Reduction' column notice the small amount of reduction for PS 6 (LR 47-53%) Quality setting. If interested why AND why you probably shouldn't use PS 7 (LR 54-61%) Quality setting see this post:
http://forums.adobe.com/message/5641903#5641903