Stretching Academy

starfield

Hi Adam,  just saw the new Stretching Academy module.   You must have been reading my mind as just the other day I was thinking, "wouldn't it be great if there was a course that reviewed all the different stretching techniques."    Once you finish Histogram Transformation, will you be covering some of the other stretching tools like ArcSin stretch and Exponential Transformation?   One of the things would be super helpful is a big picture understanding of not just how they work, but the types of problems each tool can solve.

BlockHead

Yes, this is the intent. Of course this is my opportunity to cover some part of GHS as well.

-the Blockhead

Terri in Vermont

Hi Adam, even though I’ve been doing this for a while I sometimes go back to pick up on new tricks that I’ve not learned.   Going through stretch academy was no different.    I picked up on a few things that I didn’t use previously.    GHS is new to me as well, and while I effectively did the same thing manually in the past, it’s a new way to do things that might save time versus editing curves manually and forever adding new points that I don’t want and subsequently having to delete them.    The early videos in the academy were a bit repetitious, but maybe good for those unfamiliar or newer to editing.

Terri

BlockHead

Hi Terri,

Since I may make this available as a stand alone thing- I thought it best to approach the topic as if people had not seen the information before.

-the BLockhead

Charles Schreiner

Adam, 

I decided it was time for a review of the basics. One thing that perplexes me is when I drag the STF new instance triangle to the Histogram Transformation bar after I have stretched the image in STF - sometimes the data and graph in HT will show the expected values that reflect the STF stretch, but often will retain their original values (0.0, 0.5, 1.0) and the line graph remains linear. Yet the stretch is there - if I then move the new instance triangle from HT to the image, the image is permanently changed. If I save it and reopen, it is stretched. There's got to be some toggle somewhere that switches the HT values/graph display on and off is all I can imagine. 

I just checked; I am completely up to date. Can you suggest what might be happening. 

Thanks,

Chuck

PS: When I drag the STF new instance to the HT bar, the hourglass shows appropriately. But nothing happens in the HT display. Screenshot attached of post-drag results.

BlockHead

I have a video about this demonstrating it. I can't remember where right now..but I think I did an update to demonstrate. The difference is when you are working with a RGB (multichannel) image compared to a grayscale image. To see the values that you think are unchanged... look at the individual color channels with HT after the transfer..and you will see the black point, midtones, and white point values you are expecting. Remember when you have a color image.. you are working with three images. So the RGB/K is only referring to lightness (K)- but you are operating on individual channels.

By the way, I challenge you to find another content creator that answers this question correctly. :)

But first... let me know I am correct.

-the Blockhead

Charles Schreiner

Well I'll be damned. That's the trick! I can't tell you how many times I've tried to figure this out. Thanks!

Two thoughts. First, you responded at 12:30 AM. Don't you sleep? Second, your level of detail and grasp of Pixinsight is off the charts. It takes some savvy to follow you sometimes, but you're so so so reponsive to offer help. That's actually more impressive, meaningful to me than your extraordinary knowledge base!

Cheers,

Chuck

BlockHead

Well... let's just say some questions I can answer in my sleep... :)

-the Blockhead

Charles Schreiner

If I had played another 3 minutes of the lesson before posting, you explained it. Oh well. 

Good stuff. Gonna stick with this. 15-30 minutes maybe every other day is my target. Take a year or two.