I'm trying to adapt the excellent Design 7-9 sets from i13 for use with gamma correction in Poser Pro 2012, and I could use some help/advice please.

First, here is a render using the default values and sample scene the Design 9 package ships with, with GC turned off:

Here's what I get when I turn on GC, remove AO from the lights, and set gamma 1 on the transparency maps:

Everything became much darker and lifeless. (Please ignore the weird polygons. I've accidently set 'smooth polygons' and it did not like it...)

Now then I've looked at the materials. I could not find much that seemed suspicious... The only thing was the 'Reflection_lite_mult'. I've read somewhere that it should always be turned off, so I've tried that. Here's the result:

Not much better :(

I haven't changed the light intensities yet, as I wanted to be sure I'm not missing something.

Here are the texture gammas I've changed, and my render settings for the GC enabled images:

My main aim here is trying to learn how to adapt purchased content to GC...

I'd geatly appreciate some advice/ideas regarding what I should be look at next!

 

I would turn down your diffuse_value to something other than 100%.  Try 85 or lower.  Definitely lower your light intensity; with Gc lighting can be set to a lesser value. 

Now, exactly, what are you trying to achieve?  Since it is an interior you are trying to light balance, I would recommend striving for some realistic light placements with point or spot lights.  Especially with inverse square attenuation to give you a light fall-off affect.

I assume it comes with lights?

It's likely that the lights themselves use shades of gray in their color chips - a no-no when trying to switch between non-GC and GC. It changes the light levels.

To recover the original lighting level (which you may want to lower again later) you need to read the values in the lights.

Given original light:

RGB X, X, X Intensity Y

You would switch to

RGB 255, 255, 255, Intensity (X / 255) * Y

The reason is that enabling GC does not just do gamma correction at the end. It converts all incoming material to linear values - this involves anti-gamma correcting incoming colors. The point of enabling GC is linear workflow, not gamma correction. GC as a final step in linear workflow somehow has come to be the name of the whole thing. This causes a great deal of confusion. The checkbox should be "Linear Workflow" not "Gamma correction".

So - suppose you had a light with RGB 180, 180, 180 and Intensity .7. The effective illumination with GC (Linear workflow) enabled is:

((180 / 255) ** 2.2) * .7 = .325

whereas the intention was

(180/255) * .7 = .494

So in that case you'd switch to RGB 255, 255, 255, intensity = .494 or 49.4%.

Then you have the same amount of light as before.

 

First of all, thanks for the replies!

@hborre: At this stage I was not trying to achieve anything other then matching the initial look that came with the set (without GC). In particular I was missing the vibrance and contrast. Also I know that it is good advice in general, and I've read it before, but I also always find it very confusing when someone has a problem with the image being too dark, and people suggest that they should lower the light intensities...

 

@BB: Thanks! I've saved that to a text file :) I am aware of the whole "linear workflow". I've read quite a few of your posts here and on RDNA on the subject and I'm all on board :) I also remember that the subject of color swatches was discussed somewhere, but somehow I thought that when you turn on GC poser will do the "anti-GC" phase both on the images and the color swatches, but perhaps I remember it wrong...

Also a related question: You are suppoed to set the gamma of "value" type images to 1. But sometimes the same image is plugged to a bunch of color type of channels as well as value type channels and you can only set one gamma per image...

What's the best way to solve this? I guess, rather then creating and loading a separate copy of the image just so that you can set the gamma independently, one could just set the image gamma to 2.2 and add an adjustement node before connecting it to the value channels?

Or (and this just occured to me) if the image was created with the diffuse channel in mind then it may require gamma correction for the value inputs as well?

Which actually leads me to a question that I always wanted to ask: I understand in theory that you do not want to (anti) GC value maps like bump, transparency etc. However what I always wondered is that if the image is/was created in Photoshop or similar, then Photoshop would not know that the image was meant to represent values and would (I assume) perform the usual gamma encoding when saving the image, wouldn't it? And if yes, wouldn't we need to compensate for this to get back the intended gray levels?

Back to the image at hand:

I've adjusted the light levels as instructed and it helped a lot:

Note however that the image is still not as "crisp" as the original. The texture clarity (?) and contrast on the sofa is still not as good as the original. The column at the stairs and the table is overexposed/blown out. The lights now are probably too much. (Note: the lighs intensity varies between 35%-60%-ish...) The reflections on the lapshade look weird and for some reason the left side of the bug vase below the stairs lost its green color... I wonder if this last thing is related to me unchecking the lite multiplication or to the fact that the marble texture is added on top a greenish base diffuse color (0 68 68)...

I originally did not touch the supplied lights as originally I did not think there was anything fundamentally worng with them (Apart from turning off AO, which should be unnecessary with IDL, right?) However I also did a test render where I've thrown out all the lights and added just a single infinite light at 0.9 intensity. Here's the result:

This is now much better. Though some things could be improved. Especially with the small objects below the stairs.

Some specific questions:

• One of the original lights is a diffuse IBL with just a color. In fact it had a "simple color" node attached with a gray color to the "color" input. The light also has a diffuse_color channel as well which was also a gray color. What's the difference between the two channels? In the first image with the adjusted original lights I've removed the simple color node from the color channel, set it's color value to white and adjusted the intensity based on the formula from BB. I did not know what to do with the diffuse color channel gray value, so I've just set it to white as well...

• A lot of the surfaces have a non zero ambient value, often combined with a non-white ambient color... How does one deal with that? (I've seen a lighting training video suggesting that adding an ambient component to all sufraces is an acceptable way of providing general ambient lighting, but I've always found it a bit strange...)

• Some of the maps are added onto non-white (and often non-gray) base diffuse, specular and other channels. How does one adjust thise (if at all)?

• Often the same image map is linked to amost all the base input channels... This seems to make it rather difficult to deal with them properly...

 

Again, many thanks for your help in advance!!!

I will not attempt to answer all your questions, still need to ponder the exact response.  However, IBL does have a tendency to washout shadow areas strictly because it is just a general, overall ambient lighting.  I would delete that immediately given your situation; I find no beneficial use for it in PP2012 unless you use it at extremely low values. 

Any active ambient channels present in the scene can produce bizarre results because ambient channels are designed to make your object "glow".  A prolific cheat back in earlier versions of Poser but not necessary in the current IDL Poser iterations.  Those I would also eliminate.  The vendor is trying to convey a mood using MAT Room tricks which does not fit into your workflow. 

As for the gray chips, I think BB has explained that situation thoroughly. 

I have come across the same problem with colorless images used for color input.  In most cases, I leave those alone unless I can come up with a better alternative.  BB might have an reasonable explanation about how to handle those connections in a realistic fashion.

Just some further experiments regarding the disappearing green in the vase:

If I leave GC off in the render settings and look at the material this is what I see:

As soon as I turn on GC in the settings and come back this is what I see:

Now I assume this is because the green diffuse color (among others) is being adjusted.

The original color is 0,63,63. Using the gamma formula you get:

((63/255)**2.2)*255 = 11-ish

Which is pretty dark and would explain the gray look.

So I thought I adjust the color in the opposite direction:

((63/255) ** 1/2.2)*255 = 135

So I set the color to 0,135,135 after which I get this:

Now we indeed have some green back, but it is too light. I had a suspicioun that it has something to do with the ambient value being added as it is obviously not the spcularity. And since it was clearly to light this time I've adjusted it the other way around from 0.3 to (0.3**2.2)=0.07 and I get this:

Now this is very close or identical to the original in terms of color. (The specular highlights are softer, so clearly those need adjustment as well.) Alternately I get the same result if I adjust the ambient color instead of the value. e.g. from white to 115,115,115...

What I do not quite understand is why I needed to do the adjustment in the opposite direction to that of the diffuse color???

I have that set and at this second I am no where near my copy of Poser to create a render.

I will toss this out to BB and hborre as some added information in your quest to help.

I think the stock lights have AO and or there is some AO hooked up in the material rooom to various pieces.

I also seem to remember the lights of the presets (pz3's) are way different and too strong compared to changing the lights out with the lt2's.

To bajvor, have you tried applying one of the light sets for the light tab vs using the lights from the presets?

If you're using IDL and you're rendering in Poser 9 or Pro 2012, you will want to rework all materials to take out any Ambient. Otherwise, all items in your scene are glowing as if they were all made of light bulbs.

well, I set all ambient settings to zero, added a envrionsphere, loaded a texture which would be somewhat appropriate ( an interior view) and swapped the single color of the ibl lite to an hdri matched to the sphere texture, added a back wall (which didn't exist) to close the scene from behind and added a while paint texture to it. Then I changed the  infinite light to a point for more drama since its placement, implied to me, a glass wall of some kind on the balcony reached by the stairs. I then turned on shadows for the fill lights, in reality all lights create some kind of shadows even for master photographers with lots of reflectors and assistants of which the shadows were assigned as raytraced. Last but not least all the textures were set to crisp. Oh and I changed to metal shader to a basic chrome instead of the sphere mapped in the original.  Here's what I got:

Pretty spectacular. The reflection on the lamp is lovely, too.

That looks great. The reflective surfaces really do pop... but also the soft furnishing surfaces (cushions, upholstered items) look really good too I think... I'd say that its the subtlety of the shadowplay on those that really makes it for me

yeah that's a gorgeous room

I believe that I have that particular set in my Wishlist. Now I know for sure that I will have to rework all the textures, especially to get rid of all the ambient settings. Thank you so much for posting this thread and letting me know this ahead of time. I am supposing that the maker of this set does not have Poser9/Pro 2012 so doesn't know to ditch using ambient on textures unless you want something to act like a light object.

Guys all this talk about new prop-based lighting in P9/PP12, how ambient (glow) should not be done, and how some vendors are perhaps understandably not familiar with it - it's wrong. It is NOT NEW. It's been there since P8/PP10. 

It's how IDL has worked for 2 years now. It's what I showed in my freebie scene, "Poser 8 Soft Studio Lighting with IDL" - posted

January 15, 2010

NOTHING HAS CHANGED other than a bunch of people started paying attention after I showed amazing new skin shaders that work without lights.