Processing with RPP

Started Jan 20, 2013 | Discussions thread
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mark-vdi Regular Member • Posts: 401
Re: Processing with RPP (combining with Accuraw to pull maximum detail from RAF)

I started to look at the best way to get the highest level of detail out of the RAF from the xpro1.  THis was based on my own deep personal dissatisfaction with the ooc jpeg, ACR and C1 renditions all of which produce the well known watercolor, bleeding or ‘patchwork’ effects in areas of heigh detail. The method I finally found which produced the best results was based on the RPP which brings out a massive amount of detail from the xtrans sensor but suffers from strong edge artifacts.  To get round this I published a method of exploiting the ooc jpeg to provide an edge mask without diminishing the detail of the RPP rendition.  This however fails for the 18mm/60mm lenses due to the in camera lens correction which is applied to the jpeg which RPP does not read - thus at the pixel level the RPP and jpeg renditions do not align.  I have now managed to use Accuraw (Beta Test) to generate the same edge profile (this also does not read the lens correction) enabling the method to be applied to the RPP rendition.  Why don’t I just use Accuraw alone - this also produces edge artifacts / patchwork rendition / bleeding if the color noise suppression /post demosaic filtering is used to remove the color moire.

Here the method in detail (sorry if too detailed for those already familiar with the commands) for anybody who is interested - it sounds convoluted but actually can be standardized quite well and the PS (for me CS5) part is automated with 2 actions.

RPP rendition:

  1. turn off chroma blur, dot noise reduction, sharpening and local contrast
  2. set white balance, exposure, compressed exposure, contrast, saturation, blackpoint, film rendition etc as required.
  3. save as 16bit lab tif

Accuraw Rendition:

  1. Sharpening to zero
  2. Radius to zero
  3. Color noise reduction to zero
  4. luminescence noise to zero
  5. post demosaic filter to zero
  6. Set exposure and contrast as required (over exposure and too strong contrast are ok since this rendition will eventually only be used to generate an edge mask)
  7. export as 16bit tif

In Bridge: Open each rendition in ACR:
(here you can check that the original exposure/contrast white/black points are appropriate)

  1. add color noise reduction add vibrancy to recover from resulting desaturation
  2. remove chromatic aberration / Defringe if required (If the motif will allow reducing the saturation and or changing hue of the purple slider amy also help here)
  3. slight recover sharpening 30 Amount/0.5 Radius/30 Detail/no mask
  4. For the 18mm Lens: Manual transform lens correction: Distortion +22, Scale 107 (This translates into a massive loss of data but corresponds to that needed to +/- 'completely' compensate barrel distortion - and explains why on the whole people prefer the 35mm lens in terms of detail - but thats another story.)
  5. open image into PS

In PS:

1) Add Accuraw rendition as a layer on top of RPP rendition.Gives two layers “Background” and “Layer 1” and all further actions have been animated based on this name convention

2) duplicate Layer 1 (Accuraw rendition) and turn off layer 1 and background

3)add b/w adjustment layer add levels layer - adjust levels to dramatically blow out most areas above mid grey that will not be needed for masking =White triangle from 255 to between 180-200

4) command shift e to combine layers = layer 1 copy

5) Filter / Stylize / Find Edges

6) Add new levels adjustment layer to us this to modify ‘Layer 1 copy’ to push to white those areas that you don’t wan’t to mask (none edges!)

7) Select color range (fuzzyness 100) - ok

8) modify selection contract 1 pixel

9) modify selection feather 1 pixel

10) command shift i to inverse selection

11) turn on layer 1 and add layer mask - selection will automatically become layer mask

12) turn on background and turn off layer 1 copy and levels

13) adjust opacity of Layer 1 = edge mask to minimum required to mask edges ca. 30-50%

13b) if any color moire still remains a quick trip into Lab and a local blur to the a and b layer will usually mitigate this!

14) sharpen each layer as required - I do this with two highpass filter layers: Duplicate each layer, sharpening these duplicates with unsharp mask (very little required for RPP layer), blending the layer style for these layers (this layer white 220 - 240 and underlying layer black 10 - 20), blend mode = overlay and add filter / other / highpass = 1,8 pixel

15) Copy layer mask from Layer 1 and add this to the highpass sharpening layer above this layer.

16) adjust opacity of the two sharpening layers to taste ca 20-40% for highpass layer above RPP layer and 10-30% for Accuraw layer

=> Finished . . .

NB I am very happy to help anybody who wants to incorporate this into their own workflow

Here are three of my own natural images performed using this method as jpeg and tif for 100% pixel viewing.







Here is an 18mm shot of a building with the lens compensation for the barrel distortion described above applied  (Thanks to archi*dss  for providing original RAF - i don’t have the 18mm lens myself)



Here (again) the DPreview test picture (using the RPP/Jpeg version of the method):

And as for me, I finally believe I am getting the best possible information from the xpro1 and find my 'love-hate' relationship is very much leaning towards love!

Cheers, Mark

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