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Old 17-02-2014, 01:07 PM
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gregbradley
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I think Mike is talking about a different thing. Using a mask and blending it in lighten mode or enhancing what is there and then blending that in on the object of interest is only enhancing data that is there in the first place.

Some brush tools and lassooing can cause an artificial structure based on the borders of the selection. I take he is referring to that.

As far as R Jay goes I don't know that he adds false detail to his images but rather super heavy colour saturation and stretching to coax out every last drop. He may have features enhanced out of proportion to their relative brightness - so relative brightnesses are changed heavily
but I don't think that is creating an artificial structure that does not exist. Much like Hubble narrowband showing up structure that regular colour does not.

Don't forget he uses 20 inch RCs and dark sky sites and super long exposures with good cameras and mounts. The 20 RCOS scope is probably the most premium scope around and its too bad they went out of business, but they got some amazing data from those scopes.

Greg.


Quote:
Originally Posted by alpal View Post
Yes Mike but Ken Crawford wouldn't agree with you:

http://www.imagingdeepsky.com/Presentations.html

He "digs out the details" using masks.

I often use masks to get the desired result but in a different way e.g.
An inverted layer mask is great to get rid of noise in low signal areas
but what about when there is noise in a high signal area?
The only way is to:
reduce noise for the entire picture until the noise in the area you want is reduced
then make a hide all layer mask,
then paint on the mask for the area you want to be reduced.
You can see the results as you paint.
Then you can blur the mask & reduce the opacity to make a perfect seamless blend.

I wouldn't have known that unless I had watched all his videos.

You can also do the same thing to sharpen a certain area while
leaving other areas alone - also -
e.g. at the edge of Centaurus A it is very bright & the tiny details
get lost in this brightness.
A selective adjustment of curves along the edges will show those otherwise hidden details.
You can "dig out the details" in such ways without
having a false image - it's just using the data you have.

Also - if you want a 3D effect then it's great to make the front area of
a target ever so slightly brighter.

Ken's methods allow you to give more impact to your images.

I will continue to use such methods but only in special cases -
it's too much work to do an entire image that way.

cheers
Allan
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