Harold Kip posted this reply to some of my shots and I thought that maybe my response might be of some use to others.

http://www.simviation.com/cgi-bin/yabb/YaBB.cgi?board=paywareshots;action=display;num=1156652185

Here is Harold's comment:

"Stunningly great shots as every Michael! I live the Lynx -our Navy has them too - and Berkley Castle is just soo gorgeous!

But in some images you still have 15-20 kb to work with. You could try compressing these shots a little less so the quality of your work would even shot better! It might be what we Dutch call "fecking an ant" but if you'd like to advertise your business with these shots too (and you do it soo well) you just want to take away any imprefections, how little they might be ...

ANd 15-20 kb is 20% ... and I don't have to tell you that a 20% growth is a huge difference"

and my responses:

Harold,

Possibly you see things that I do not or you have some knowledge that I do not so I'll try to explain my process and if you have anything to add than I'm sure it would be interesting.

1) I run my sims at 1600x1200 on maximum settings so that the detail in the shots even at long distances is very very high

2) When I need to reduce (compress) their size to 800x600 (maximum allowable on this site) their weight  is too much for this site any further reduction(compression) increases weight even more and distorts details.

3) So a shot like the 2nd shot in this series with maximum compression (reduction in size) for this site would weigh about 355 KB and be much too large.
 
4) At this point I now need to reduce compression as much as I can and still stay within weight (100MB)

5) When I am using ACDsee (my editing program) I also use progressive encoding and set Color component sampling at 2:1 Horizontal and 2:1 Vertical

6) This allows me to preserve the actual colors that I see on my screen.

7) However with compression (reduction in size) this type of encoding distorts bright reds and yellows so it has to be changed when those colors are used which further increases the weight.

8) Once I have done all this I now can reduce compression and increase quality. So in shot 2 for instance I'll use a reduction of about 75-80% which brings the weight to around 62MB which is acceptable for this site. If I reduce compression too much the weight will be over 100MB.

9) I could by using adjustments raise that to say 75MB or more (if I saw a reason)  

10) While I could decrease compression and increase weight on certain shots I would run the risk of not being able to present the series in the manner that I wanted (6-7 shots under 500MB) and in any case there would not be that much of a visual improvement.

11) This could only be done with shots that have a low level of background.

12) Each of my shots in a series (the story I am telling)  is checked by both myself and my wife (a graphics artist) to make sure that it has no visual anomalies and given maximum weight for this site ( 500 MB allowable).  

13) I use a high end graphics monitor called a Viewsonic G220fb ( very very accurate) so that I can be sure that there are no errors in what I'm seeing ( After all I do this for a living also)

14) Each of the shots within this series is between 59-77 KBs. There are 7 which gives a total of 465MB leaving me with 35 MB to play with not 20% (remember it is a series) which I would have used had there been any reason (that I or others could see) to do so.

Since you seem to be seeing things that I am definately not I would love to see a series (6-7 shots none over 100MB weight  and no more than 500 MB in total) of your shots. Who knows maybe, if you'd like, I could use your screenshots with some of the companies I work for.

As a Microsoft Graphics Engineer it has taken me a long time to develop my understanding of how compression works but I am always open to learn new things.

As an addendum,

I could  raise each shot in the series to say 70MB dependent upon background etc (some are over that)

At 7 shots to the series that would raise the weight to 490 and with added little bits of weight would probably be over 500 MBs.

I could also use less shots and change the series if I saw a reason (which I don't)

In some cases this would reduce the weight of those shots already over 70 and in others increase the the weight by 10-20%.

A 10-20% reduction or increase in weight is not enough to create a visual difference (weight and clarity do not change at the same rate).

Such a weight increase would in fact only translate to a clarity increase of 1-2% viewable on a standard monitor (less on LCD than on CRT) with 4:3 resolution at 1280x1024 75MHz on the web.
 
A widescreen monitor or other LCD monitor would have to have a response time of 2-3ms to reproduce what I see on my monitor.

If you have such a monitor and remember it would also have to have a 1600x1200 resolution with an 85Mhz, refresh rate than if I sent you a full size shot you would see it as I see it.

Once reduced this would be true also.