Could help but sharing this experiment I did. If you look at the picture below,it is the KV1 for the B&B, the smaller one is the 1/72 scale T34/85 from Dragon....both are air-brush from the same bottle of paint....

The KV1 only had pin wash to it whereas the T34/85 had filtering done for the entire model....and it is so much darker.....both pin wash and filtering are using W&N raw umber...

This really set me thinking....from now onwards, should I filter since it darken the model badly.....

Anyone has simiar experience similar to this one ?

You didnt filter. By using a uniform color over the whole model you basically just gave it a really thin wash. To filter you use different colors on different areas to create VARIATION in tonal quality. Also was the model dead flat when you applied you tint? Filters need to be done over satin.

HTH

Mike,
You have to be careful with these kinds of comparisons when you're dealing with models of two different scales. Simply put, paint from the same bottle, diluted to the same ratio and shot with an identical pressure, will always look darker when applied to the smaller of two vehicles. So this kind of experiment might not be as conclusive as first imagined.
That being said, you are correct to assume that an overall wash, as you applied it, will certainly darken the model. But filters were never really intended as an overall wash. They were "developed" as a way of creating a multitude of tones and hues, accentuating the overall color subtly, rather than altering it's tonal quality completely.

Mike Kirchoff

Hi John

For a green vehicle, what different color would you use suggest for filtering...so far I have been using only raw umber....

BTW, the model was gloss over ...if we see the turret of the T34/85, it is still quite shiny...

After the initial post, I use naples yellow for filtering.....on the small T34/85.....it is lighter color now....very interesting finding....

and in-case you are wondering why the 1/35th KV1 is still there...I found out by accident if I placed it there, my camera will be able to take sharp picture of the T34/85 and the KV1, I am sure there must be some explaination to that as well.....


After Raw umber filter


After Naples yellow filter....

I think you almost have it. Go back again with the brown - but just on verticle panels and see what happens!

My guess is it has something to do with what tank your camera is focusing on, and the depth of field. If you camera allows you to change the depth of filed, like with different "shutter" speeds or "f-stops" that might allow you to take sharp pictures of the smaller tank without the larger one in the frame.

Im just starting to mess with filtering, so far, I kind of like it. It does add a different dimension as to how your kit will look like when finished. But, it takes time to "master" it like any other technique.