Linear workflow (LWF) the easy way

Even after a few years since linear workflow (also known as gamma 2.2 method) first “appeared”, there still is quite a lot of confusion around the subject.

This is caused by the fact that there are several methods to achieve the same result and several tutorials on the internet most of them explaining different workarounds.

In this tutorial I will try to show all the steps that I use for linear workflow (working with 3ds max and vray) and keep things as simple as possible.

Bellow there are 2 images; the first one is rendered without linear workflow while the other one is rendered using this method. Although the second one looks much more natural, due to the even illumination and without color bleed, both of the scenes have exactly the same number of lights with the same light multipliers.

Click on the image to view a higher resolution rendering

Step 1
Go to “Customize”, “Preferences” and click the “gamma and lut” tab.
Check “Enable gamma /lut correction”, type 2.2 in the field next to “Gamma”.
Under “Materials and Colors” check both “Affect Color Selectors” and “Affect Material Editor”.

Step 2
In the material editor, select one of the materials and click on the texture in the diffuse channel. In the Bitmap Parameters rollout, click on the path of the bitmap and in the pop up window, under “Gamma” check override and type 2.2


If you haven’t started the scene from scratch and you are using an older scene, you must repeat the step above for all the textures that you have used.
This is what most people forget to do and as a result they end up with washed out textures.

Step 3
Believe it or not, you are now ready to render :)
The only thing that you need to do when the rendering process is ready, is to save the file as an .exr format (you need a 32 bit image, not an 8 image).
If you need to convert it to a jpg, open the exr file in photoshop, click on “image”, “mode” and choose 8bits/channel.

Just out of curiosity, you can try to save the image as a jpg directly from the render. You will end up with a dark rendering. This is because the gamma is not burnt in the image, but with the settings shown in the previous steps, you have set 3ds max to display it correctly.

If for some reason you need to burn the gamma into the image, you need to activate the Vray frame buffer, and under the color mapping options change the gamma from 1 to 2.2
I really don’t recommend doing this tough, because of the loss of quality.

The advantages of working with gamma 2.2 are obvious… less lights are needed to setup a lighting rig for an interior scene, less color bleed, faster rendering times, etc.
I use this for almost every daylight interior scenes; for interiors with night illumination I tend not use it since I find it easier to get more “drama” in the renderings, the old fashion way.

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41 Comments
  1. jackieteh says:

    Thank you for your explaination, i will give it a try, hoping i could get the same result as your do here.

    bytheway, will you make a tutorial of how to make a spiral staircase from ground floor to 5th floor?

  2. jackieteh says:

    Hi Mr.Alex,your website is back,congratulation!!
    i have try the LWF for several day, but still facing some problem about which color mapping i should use and also textures show out blur and some weird white spot too.

    may i have your email address, so i can send some of my test rendering images to make you clear on what is my problem is.

    thanks in advance.

  3. Cgdigest (at) gmail.com
    Send me the details and I’ll be glad to help.

    Best regards,
    Alex

  4. jackieteh says:

    Thank you for allow me to send my work to you,
    i have just sent it,
    perhap i can learn more from you.
    thanks in advance.

  5. jackieteh says:

    thank you for your explaination.

    i have just sent the max file to you,
    please check your email,
    and hoping to learn from you.

    thanks in advance

  6. Thank you Alex very nice tutorial

  7. @jackie teh – Thanks! I will check it out and try to do that case study these days.

    @Alexa – My pleasure. I’m glad you enjoyed it.

    Best regards,
    Alex

  8. jackieteh says:

    Thank you Mr Alex, and don’t forget the spiral staircase tutorial too. =)

  9. Srinivas says:

    Nice tutorial. Thanks for posting it.

  10. pep says:

    thanks for the tut., but, by the way, like you said, there is so many information that i dont know really which steps follow :(.

    in this case, for example, we have to change de color mapping too, and the “input gamma” in “preference settings”….so finally we have the same with those differents ways?¿

    best regards

  11. pep says:
  12. First of all, thanks for the visit pep (and for the feedback you sent me via email).

    The tutorial you are referring to is a bit old, and was done before the 1.5 version of vray came out.
    As you can see, in the next step it advices to change the parameter of the “inverse gamma” to 0.4545, which is not needed for vray 1.5 and above.

    Best regards,
    Alex

  13. monalisa mohapatra says:

    thanks for such a great help for my study…….

  14. vizdak says:

    the tutorial is very nice, although i have a question regarding the use of archshaders in vray material. when ever i use it with gamma 2.2, the result is washout. is there any other way to make the color correction other than manually changing the color parameter of the arcshaders??

  15. Adrian says:

    This really is the best tutorial for gamma linear workflow

  16. yoursnavin says:

    hi,
    nice tutorial…..u wrote it in the easist way to understand…nice job alex

  17. mira/bangladesh says:

    hi,
    very nice tutorial.i got help full from this tutorial.carry on.thnx a lot

  18. Huzefa says:

    Hi,
    Very informative, good tutorial thanks.

  19. Lacan says:

    How would you go about using this with say some premade tree models (or any objects that you might merge)? Would you have to edit all the textures in each model so they conform to the 2.2 gamma/lut before merging them with the scene?

  20. Friendlybeaver says:

    First of all you do not have to change the gamma settings in all textures, you only change the input gamma value in preferences. The same goes for the “black” jpeg. You change the output gamma to 2.2 and your saved 8 but images look just fine.
    As for saving the exr, hdr or any other 32bit format you actually saved it as a 1.0 gamma file, so you’ll get the same result without using gamma 2.2 at all.

  21. @Lacan – I usually change the gamma after merging the objects in the scene. I almost always tweak the materials of any pre-made model anyway so I am going to need the slot in the material editor.

    @Friendlybeaver – Thanks for your valuable input. Changing the input gamma to 2.2 may make more sense.
    However, changing the output gamma to 2.2 and saving it as 8 bit images “bakes in gamma” and I found it to give less desirable results.

  22. rohan says:

    Hi alex,
    I’m using vray 1.5sp2, when i followed this workflow as u said, and i also enabled vray frame buffer and saved the rendered image directly into jpeg format, but without changing gamma to 2.2 in color mapping….
    the resulting image i got wasn’t washed out but a bit dark at windows
    i want to know is…
    will saving it to exr then again saving it to jpg from photoshop gives different or better result???
    I’m asking this bcoz my photoshop 7 is not able to open exr files otherwise i would have tried it myself..

  23. Even if you have enabled the srgb button in vray frame buffer if you save it as jpeg you will notice that the saved image is a lot darker than the one rendered in the buffer, so that is not the way to go. If you need to save it directly as jpeg you must change the gamma to 2.2 in order to “bake it”.

    Saving the image as a 32bit format gives best results and further more, you will have more freedom do tweak it in photoshop.

    Does photoshop 7 handle “.hdr” images? If so, you can try that format… I believe it should work the same way.

  24. rohan says:

    hi alex,
    i tried the exr file on one of my friend’s pc in which it opened, and yes as you said it gives us more freedom in tweaking…..
    but the point i got myself confused in is..
    when i save it in exr then the resulting image at a first glance is much brighter than that displayed on the frame buffer..
    and when i save it in jpg then the resulting image is same as the one in frame buffer but not darker as u said (without srgb checked in frame buffer and gamma 1 in color mapping)…
    i must be missing something bcoz i’m not getting dark images than displayed when directly saving to jpg, might sound funny that i’m worried bcoz it looks fine..

    hope u understood what i’m trying to say..

  25. budalli says:

    Hi, Alex
    I find this tutorial very useful, as it is a relatively new method of rendering more realistic images and not many people know about it.

    I have a question about “Color Mapping” rollout in Vray 1.5 SP5. There is an option for Don’t affect colors (adaptation only). I have heard that this option is recommended to be checked when rendering in LWF and when saving float images (with gamma 1.0 of course), and unchecked for 8 bit images, but I’m not sure. What’s your take on this?

    And also clamp output should it be checked for saving float images, or not? What about 8bit images? Can you explain?

    Vray Manual tries to explain this 2 features somewhat but I’m still confused as to which specific cases one or the other option should be used.

    Thanks!!

  26. peter says:

    great

  27. fouzi mohammed says:

    Hi Alex,
    i knew am very much late in reaching this tutorial,because i never wanted to try LWF method in past.well,i see that ur tutorial is pretty much helpful and thanx for such a wonderful tutorial.
    But my concern is about the color mapping that we can use while we fallow LWF…
    like do we have freedom to try different color mapping according to the types of scene and most importantly SHOULD we change gamma to 2.2 in the COLOR MAPPING roll out too.
    Hope u will clarify these confusions

    thanks n regards

  28. @fouzi You don’t have to set the gamma to 2.2 in the color mapping roll out if you do all the steps in the tutorial above.
    You can do that only if you want to “bake” the gamma in the image, which I don’t recommend.

    @rohan and budalli – Sorry I have missed your questions. I guess after all this time you have figured out the answers.

  29. fouzi mohammed says:

    Hi Alex
    thanks for ur explanation.now it seems pretty clear.
    i will let u knew my experience with this method once after i completed my rendering.

    regards

    fouzi

  30. Sudheesh says:

    Hi Alex,
    Thanks for giving this tricks.Thanks a lot.

  31. fazane says:

    thanks a lot for nice tutorial.it is too useful for me

  32. Fouzi Mohammed says:

    Hi Alex

    Since last November am following L.W.f according to ur tutorial,n once more thx a lot for ur wonderful explanation.My experience with L.W.f is much satisfactory n it has really helped me a lot to improve my rendering.
    But still there is a confusion about color mapping in V ray roll out.Recently one of my friend shared a tutorial which strongly suggest that for a complete linear result,in color mapping roll out we must choose only linear multiply ,with gamma changed to 2.2 n don’t affect colors(adaption only) checked. I really look forward for ur expert opinion regarding this particular aspect,since u have tremendous experience with L.W.F.
    Also i face a problem when converting .exr files to 8 bit images from 32 bit.most of time i get edges of details which look like some what not as sharpen n accurate as it does look in rendered frame window.
    hope u would help me out to sort it as u did before.

    thanks n regards

  33. fouzi mohammed says:

    hi alex

    waiting for ur valuable opinion.

    thanks in advance

  34. Hello again Fouzi,

    As I said in a previous comment, you must NOT change the gamma settings in the color mapping roll out if you have already set it to 2.2 in the Gamma and Lut tab in the preferences menu.
    You don’t need to take my word for it, just try and you will see what happens.
    You can set the gamma to 2.2 in the color mapping roll out only if, for some reason, you decide to bake the gamma.

    With regards to converting 32bit images to 8bit images I am afraid I can’t help you because I haven’t encountered this problem and haven’t heard of it before.

    Best regards,
    Alex

  35. Vinai says:

    Hi Alex,

    Thanks for keeping it simple and precise..

    I havent tried this workflow yet.. I will definitely try it..
    Does switching exposure into ‘Logarithmic Exposure’ produce a similar result?
    (excuse me and help me if I am wrong)

    Best Regards,
    Vinai

  36. Hello Vinai,

    To be honest, I didn’t get to experiment with Logarithmic Exposure, so I can’t share any opinions on that at the moment.

    Regards,
    Alex

  37. khaled says:

    thanks a lot……..

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