ZlogColor Plugin Introduction

Z​-L​og​ ​Color ​P​lug​-​in ​in details

1. ​Input color space​. ​​​This is mainly for input Gamma and Gamut. ​

I​n this example​ since​ we shot with ​Z-Log2 so we chose Z-Log2. You can ​see​ t​here are​ other camera​ options available there​.

2. Gang rgb. ​You may s​et r/g/​b individually​. This is very useful ​particularly if​ you want to adjust black level.

3. Exposure stops. This is to adjust exposure ​level ​with digital gain. ​Basically y​ou ​may interpret it​ as EI. Within the dynamic range, ​one would be able to adjust the exposure​ level​. The most important thing ​to note here ​is that ​”​if you don’t get correct exposure you don’t get correct color​”​. For example, if you have over exposed image, skin​ ​tone will get washed out. If it’s not clipped, you ​would get​ details and contrast recovered with this option. It will not give you details ​that ​the sensor ​did not​​ capture but within the dynamic range you ​would​ get correct contrast and color.

4. Temp/Tint. It’s color temperature adjustment in linear space. It’s necessary when you are in mix light​ing​ condition. Sometimes you ​might not be able to recover​ the​ actual​ color temp but ​you also wan to ​avoid color artefacts with LUTs ​in post ​due to mix ​color ​temperature lighting situation.​​

5.Hue/Sat. ​For​ Hue and Saturation ​adjustment ​in linear space. Normally you​ do ​not need it.​

​6. Gain/Gain Anchor. It’s digital gain in post. It ​affects ​mostly the high​​light area as it multiplies the gain to the image. The larger value the more it’s affected. Gain Anchor means that it only affects the value above the Anchor. Making the gain larger than 1 means amplifying the exposure and smaller than 1 is reducing the exposure. Remember that gain anchor is very easy to introduce artefacts as it ​only ​adjust​s​ part of the image. Below is ​an​example of gain 1 and 3.37.

7. Lift/Lift Anchor. Sometimes we need to adjust shadow area and lift​ shall then be used​. It affect​s​ mostly the shadow and makes highlight area nearly unaffected. Lift Anchor is similar to Gain Anchor ​but​ once the data is above the anchor​ it ​would prohibit ​lift adjustment. Below is Lift 0 and lift 0.224.

8. Offset. It’s simply ​to add/​r​educ​e​ the offset of the black level. When you have black level shift, it’s the best method to adjust it. For example,​if​ you found that the white balance is correct in middle grey but the black area is too magenta or too greenish, you can remove a little green or adding some green. Check below example and note the color change of the ground area.

9. Gamma. This is a curve to amplify middle area, between highlight and shadow. It amplifies all the brightness but it amplifies ​the ​middle most. The larger value the higher middle area is amplified. Applying Gamma bias will change the equation and it basically limited the shape of the curve. I suggest to use it. Of course we also​ have​ some parameters to define which range of the curve is valid so we have gamma start/end​ option.​

10. Saturation Correction. As you know that the color correction matrix and LUTs are calculated based on middle grey so when it’s highlight or low light, saturation will be different. Also the sensors have different saturation level for R/G/B, so in extreme highlight condition like outdoor sunny day, if you over expose the image Green will saturate before R and B. Then the sky will be more purplish. Saturation Correction is to deal with such issues.

11. Output Color Space. We put ​a number of options​ in this category. Som​e ​want ​different color looks ,some​ ​​want​ different color space output and some ​want​ different log curve to be matched with existing work.