How to remove the magenta in DNG

[hammam]

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Hello,

 

I guess this question has been asked and answered before, but I don't seem to be able to find it in a search, so forgive me for asking again: while I am waiting for my IR filters, is there a "fool-proof" way to remove all or most of the magenta cast in C1 LE from the DNG files and/or PS in Tif? I have installed the M8 profiles published here, and I use "M8 generic." Thanks a lot.

[hankg]

In photoshop you can use the "select > color range tool" to isolate the purplish neutrals. Look at the mask in mask mode to make sure you have a smooth fade off. You might blur it a little as well.

 

You can then either use:

"image > adjustments > hue saturation" and move the saturation slider to the left

or if this correction is bleeding onto the edges of some other colors use:

 

"image > adjustments > selective color" and select the neutrals from the drop down menu remove magenta (and maybe a little yellow) and add cyan until you have a neutral balance.

 

Do not make a global curve or levels change as this will screw up your grey balance.

[Shootist]

Look at the STICKY post, C1 Profiles, at the top of every page in the digital forum.

There you will find a few C1 Profiles, and instructions, for doing this.

[j. borger]

Stop using the M8 generic profile and use one of those you downloaded here and convert with those profiles from C1

[jedisdl]

I'm uisng an B&W 486 IR cut filter so I don't know if this will work for you, but it may -

 

I use PS raw converter (still using original CS) and under calibrate tab, move the sliders for red hue up by 40-70 and sometimes the blue hue slider up 20-40. Seems to help with my images. Good luck.

 

Steve

[Jamie Roberts]

Hello,

 

I guess this question has been asked and answered before, but I don't seem to be able to find it in a search, so forgive me for asking again: while I am waiting for my IR filters, is there a "fool-proof" way to remove all or most of the magenta cast in C1 LE from the DNG files and/or PS in Tif? I have installed the M8 profiles published here, and I use "M8 generic." Thanks a lot.

 

If you've installed the profiles here, and you're using M8 generic, then you *aren't* using the profiles that will help you.

 

Try "Leica_M8_JHR_V1" or, if you want an oversaturated profile that needs some green / blue added but gives some interesting colour effects, try "Leica_M8_JHR_V1_Chrome".

 

Both will mostly cure the magenta blues

 

I'll do more profiles once Leica releases their next firmware, which I suspect will change the way the unfiltered camera sees colour.

[hammam]

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If you've installed the profiles here, and you're using M8 generic, then you *aren't* using the profiles that will help you.

 

Try "Leica_M8_JHR_V1" or, if you want an oversaturated profile that needs some green / blue added but gives some interesting colour effects, try "Leica_M8_JHR_V1_Chrome".

 

Both will mostly cure the magenta blues

 

I'll do more profiles once Leica releases their next firmware, which I suspect will change the way the unfiltered camera sees colour.

 

Thank you all. Thanks Jamie. Of course, I have to use one the downloaded "Jamie" profiles (the V1 in this case). Duh. But the magenta does not disappear by magic just by opening the file in C1. What are the next steps? Tweaking the WB, I guess, but how, and is there something else I should be doing, given the somewhat limited color controls of C1 LE? Thanks a lot again.

[jaapv]

Use the black eyedropper tool on a spot that should be black.

[AlanJW]

Use the black eyedropper tool on a spot that should be black.

 

If it was this easy, we wouldn't need profiles. I am far from any kind of expert on this but changing a magenta cast area to black I had thought would alter the color blanace, and I would assume lose all the show detail as well.

 

With my 486 filters not arrived yet, I have had decent success using PS2 in applying the profiles Jamie posted. I have also created some usable PS ACR profiles with a profiling tool available on the net. search for "calibrate ACR 3.6" and you will find a PS script that you can run after shooting a Gretag-Macbeth chart. I am not 100% pleased with my efforts, however, so I am searching for the magic bullet.

[jaapv]

It is not that easy; it sets the black point. The profile will help of course, but one needs to set black and white and preferably grey points to enable the profile to do its job in a coorect white balance. It cannot know what part has to be black if you don't tell it. The magic bullet is of course the IR cut filter....

[Jamie Roberts]

Thank you all. Thanks Jamie. Of course, I have to use one the downloaded "Jamie" profiles (the V1 in this case). Duh. But the magenta does not disappear by magic just by opening the file in C1. What are the next steps? Tweaking the WB, I guess, but how, and is there something else I should be doing, given the somewhat limited color controls of C1 LE? Thanks a lot again.

 

Setting the WB is the next most important thing to do in C1. In mixed light, this can be tricky, so set it for the light that is strongest.

 

You can also remove a cast with the color wheel in C1 (actually, the color controls in LE are very good), on the WB tab. You can adjust the hue and saturation of the cast too with the vertical sliders (Windows--don't have a Mac here).

 

Then, yep--set the white point and black point with the sliders, and you should be pretty darn close.

 

I should have qualified my previous remarks, of course; the profiles will remove most of the magenta. Not all of it under heavy IR conditions (usually tungsten). They will also remap the saturation quite a bit.

 

FWIW, I have every confidence that Leica will fix a lot of this in firmware (since we can obviously do quite a bit with a software profile).

 

To make sure you don't have IR contamination, though, in very strong IR light, you're going to need a filter.