Hello gang, My hope is that you are not sweltering too badly through this long, hot summer. I'd like to share a new processing technique with you, which might take some of the heat off! Many of you are likely familiar with HDR (High Dynamic Range) techniques for terrestrial photography. You know- taking a minimum of three images of the same subject with different exposures, to maximize shadows, midtones, and highlights respectively, then blending them with Photoshop's Merge to HDR Pro or similar routine in other software. The results are often WOW, a unique and dynamic look, though artificial looking if overused. If used subtly however, it can be very powerful, and if used more emphatically, it can create surreal and very cool images indeed.
What if I told you that you could partially take advantage of HDR's 'pop' in astro-imaging, and with a single image? Have a look under Image/Adjustments/HDR Toning. While not a true HDR merging of disparate images, it is a very powerful processing tool. Its 'wow factor' is akin to, but more dynamic than what is obtained with Shadows/Highlights, a nonlinear stretch, used as an alternative or in conjunction with Photoshop's Curves. I have stated that using S/H exclusively is 'dangerous medicine' and doesn't yield the realistic look of Curves. The same is true of 'HDRT'. I recommend processing images with IP4AP techniques using Curves as the primary tool after DDP, then consider finishing off with S/H. For a real slam dunk however, particularly for nebulae- try HDRT!
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| Basic Image Processing |
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| Try my settings, but experiment! |
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After HDRT- Wow!
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I might suggest that you blend in the HDRT as a Layer with reduced Opacity. You can also use Layers' Masks and 'Blend If' if you don't like its effect on the entire image. I think you'll find however that a reduced Opacity of 25-75%, it will do just fine. As you have to begin with a single-layer duplicate anyway, consider using a Pseudo-L or Luminance for the HDRT application.
Be advised that at the bottom of the dialog is an expandable section called Toning Curve and Histogram. The great Ken Crawford is having much success with subtle adjustments there for his high-resolution work, so experiment here too if you have a mind to. For people like me who like powerful results quickly however, don't worry about it to start!
Until next time, this is Warren Keller for IP4AP- Image Processing for Astrophotography sending my best!
