Safe Color Range for TV

[Stregga]

I was playing around with a few DVD Menu's and added some effects that appeared really well on my monitor but when I put them on the TV they looked lousy!

I am assuming that this has to do with the difference in color range between my monitor and my TV.

I know I've seen a post on a similar topic however I cant find it. Can someone please direct me or provide me with what the safe color range is so that when I edit menu's in photoshop and add additional effects I don't waste a lot of time creating an effect that will look poor on TV. I know that having a dual tv/monitor setup would reduce if not eliminate this problem altogether, but for right now I can't swing the setup. Your assistance is greatly appreciated.

[Bob]

If you are using Photoshop and not Photoshop Elements, you can use proofing to judge your results and make adjustments. PAL and NTSC profiles are included in Photoshop. In View>Proof setup, select custom and NTSC or PAL. Then, enable Proof Colors and Gamut Warning.

You generally need to adjust the black and white points. Add a levels adjustment layer and, in the output area, set black to 16 and white to 253 (or you can set your black point and white point to these values). Photoshop also include an NTSC filter under filters>video which can be used to restrict the gamut.

That should get you started.

[Stregga]

Bob,
Thanks for the reply. I adjusted the settings as you stated, and I got a gray line around some of the objects in the menu. Not sure what I am looking at and how do I know what is not going to appear as it should. I did turn on the color and gamut warning options, and I didn't get a popup window telling me there was a problem. Also, there were two options for proofing on my version of PS(CS3). One was for SDTV NTSC and NTSC (1953), I picked the SDTV option. What's the difference?

[Bob]

The gamut warning feature does not generate a popup. Instead, the areas of the image that are out of gamut, by default, appear as gray (you can change the default color, if necessary). The gray areas are the ones that are going to change.

I'm glad to see that CS3 has updated the profiles. I'm still using CS2 which doesn't ship with those profiles, I'll probably upgrade to CS3 in January. NTSC (1953) is the original specification oriented around analog broadcasts and CRT TVs. It's now considered obsolete for most uses. The specification now is oriented towards digital workflow. SDTV NTSC is the proper choice. In a full video workflow, SDTV NTSC reflects capture on SD digital video equipment and display on standard definition TV. There is also a HDTV (Rec. 709) profile for high def workflow.

[RJ Johnston]

I believe that the SMPTE-C color profile is equivalent (or almost equivalent) to the new SDTV NTSC profile. The PAL-SECAM profile is probably the equivalent of the SDTV-PAL profile. However, these profiles don't give you the "safe" color range.

Use the Filters > Video > NTSC Colors filter in Photoshop to bring colors into the safe zone. While a color may be in gamut, it may not be safe and could cause your TV image to flicker or distort or bleed. I would only use this filter for graphics, not photos.

Bob, did you transpose 235 to 253.

The reason the "gamut warning" is greyed out is because your custom profile is set to "keep RGB colors." I think that is what you want anyway. You could use "Perceptual" or "Relative Colorimetric" or "Absolute Colorimetric." Those will let you use the "Gamut Warning" menu item.

(I couldn't find an .icc or .icm file for those new profiles. There must be something new in the way Adobe is implementing those profiles. On the ICC website they talk about "are you ready for V4?").

[Bob]

Bob, did you transpose 235 to 253.

I sure did! Glad you caught that.

[RJ Johnston]

Bob,

After some more testing, I finally came to the conclusion that the SDTV NTSC and SDTV PAL profiles don't always give the same perception as the SMPTE-C and PAL SECAM profiles, especially the PAL ones. The SDTV NTSC profile seems to raise the black levels. I suppose that would give you the perception of what the image would look like if you have an NTSC DVD player and you set Black Levels to On.

If you have Adobe Premiere Elements 4.0, you might try copying and pasting the ACE.DLL (Adobe Color Engine) included with it into the Photoshop CS2 folder, after renaming the one in the Photoshop CS2 folder. That DLL in the Premiere Elements 4.0 folder contains the SDTV NTSC, SDTV PAL, and HDTV (Rec. 701) profiles.

After copying and pasting, those new profiles will appear in the list of profiles you can assign to documents in PS CS2. Hopefully doing this won't cause a problem for PS CS2.

[RJ Johnston]

I was just reminded that SDTV is digital. Since I have only an analog TV, things weren't looking the way I thought they would look. My parents have a digital TV. I always wondered why my video played on my JVC analog tv looked better than on a Sony WEGA digital tv. I have to put the Sony in "Movie" mode to get some of the color back. With this SDTV NTSC profile, I think I'll be able to get a good idea of what my videos will look like on my parents tv.

I guess I should turn the black levels off on my parents DVD player. With a digital TV and with black levels turned on on the DVD player, video looks washed out.

[Stregga]

If you are using Photoshop and not Photoshop Elements, you can use proofing to judge your results and make adjustments. PAL and NTSC profiles are included in Photoshop. In View>Proof setup, select custom and NTSC or PAL. Then, enable Proof Colors and Gamut Warning.

You generally need to adjust the black and white points. Add a levels adjustment layer and, in the output area, set black to 16 and white to 253 (or you can set your black point and white point to these values). Photoshop also include an NTSC filter under filters>video which can be used to restrict the gamut.

Bob,

We talked about this a while back and I got into the gamut problem again, and I was able to again follow these suggestions to get me out of the problem.

I was wondering if there is a way that I can set up a profile so that when I am playing around with Menu's for PE I don't have to go back an fine tune what I thought was already finished? What I mean is, can I set up a default so that when I am using colors, only those colors that will not give me problems later can be used? If so, can you please explain?

Also, when I went to my Proof setup profiles, a new one is in there. Either that or I didn't notice it earlier, but it's SDTV NTSC 16-235. Is this a better option than the current one I have selected which is SDTV-NTSC?

[RJ Johnston]

Don't know if this will help you, and not sure about CS3, but in Photoshop CS2 there are video actions for making broadcast safe luminance and saturation colors.

You have to load "Video Actions.atn" which are in the "Photoshop Actions" folder.

[Bob]

Those actions are in CS3 also. The broadcast safe luminance action just creates the levels adjustment layer I already mentioned. The broadcast saturation action creates a saturation mask to reduce just those areas that are oversaturated. The broadcast safe action simply invokes the other two in sequence.

SDTV NTSC 16-235 is provided as a way to restrict the luminance range to 16 and 235 (hence the name), it doesn't deal with chroma. It's intended to be used as an aid for conversion to a restricted luminance output space. You can accomplish the same thing with the levels adjustment layer.

There is no real way to restrict the colors. Even if you could, adjustments you do afterwards can throw them out of tolerance. Most of the time, it's saturation that causes the problem and the action can help you deal with that. If you use the action, create a "stamp visable" layer at the top of the layer stack and have it as the active layer then run the action.

[Stregga]

Geeeeeezzz Bob,

You may as well have explained to me how a nuclear reaction works. You are at a level that is like Mt. Everest and I havn't even made it to base camp. (I mean that in a good way )

I understand actions and have used some, but you guys lost me when you started talking about luminance. I have used a levels adjustment layer successfuly to correct the gamut problem, but are you saying that this can also be a saturation issue as well?

Also, I am lost on how chroma plays a part in this as well.

I did learn just by trial and error that once I started making some adjustments it would throw the colors out, but what I am struggling with is that I don't get the gamut errors when I am looking at the menu's in PS and everything looks as I would like it too. Then I burn it and look at the menu on the TV and some of the colors don't even show up. A purple highlight comes out as grey on one side of the screen and barely visable on the other side. With that said there is a motionless satin background which has different shades and saturations of the the purple, so I would imagine this has something to do with it. Which is why I am confused why it looks good in PS, but not on TV.

Even if you could send me in the right direction on how to minimize the number of times I have to adjust the colors and number of burns before I get the whole thing right, would be a huge help. I am currently working on burn #6 to get this thing figured out. A good thing they are DVD-RW's, still doesn't help much with the time issue.

Thanks for your help RJ and Bob.

[Bob]

Sorry about that!

The terminalogy gets a bit messy as the same terms have different meanings in different contexts. Rather than strictly define the terms and the context in which the definition applies, let's simplify things.

What we call a color has three attributes. Let's call these lightness or luminosity, hue, and amount of colorfulness or saturation. (there are other valid ways of defining this, but HSL or Hue, Saturation, and Lightness will do fine for this discussion).

A gamut for a device such as a TV is simply all the possible colors that the device can reproduce. If a color is out of gamut for a device, it can't be displayed by the device. What you'll see depends on how the device handles out of gamut colors. If a color is out of gamut, it can be changed to a different color that is in gamut by adjusting one or more of the three attributes.

NTSC Safe colors have have to do with the requirements of the video signal and how it affects the equipment that transmits and reproduces it. If the colors are too dark, too light, or too saturated, you can get bleeding of colors, image artifacts, and other problems. Having NTSC safe colors does not imply that your colors are within gamut for your TV. They can be safe and be out of gamut at the same time. The actions that were mentioned earlier are intended to produce color safe luminosity (light and dark values in the safe range) and color safe saturation. The Photoshop NTSC Colors filter is also intended to create NTSC Safe colors.

You should be able to get a reasonable indication of whether your colors are within gamut with the "Gamut Warning" feature. You don't need to have "Proof Colors" enabled, but you do have to specify the color space you will be checking in "Proof Setup". Under "custom" select SDTV NTSC for a digital TV and do not check the preserve RGB numbers checkbox. Enable gamut warning and your out of gamut areas should show in gray.

If you have out of gamut colors, you can bring them into gamut two ways. Manually, and via color space conversion. Color space conversion is the easiest, but you have the least control. While manually gives the most control but requires the most effort. Often, though, the color space conversion will be good enough.

If you are going to use the color space conversion method, I'd recommend that you use sRGB for your working color space. When your image is complete, use "edit->convert to profile" and specify SDTV NTSC as the profile. Converting to the SDTV NTSC profile forces the color values to be within the target color space. The default intent (Relative Colorimetric) should be fine, but you may want to try Perceptual to see which gives you the best result. Perceptual can compress the color space too much if you have some colors that are far out of gamut though. Convert to Profile turns off gamut warning. Enable Gamut Warning again and you'll see that there are no more gray areas. Actually, I think it would be good practice to do the convert to profile as the last step before saving even when you are using the manual method.

In the manual method, you target the specific colors that are out of gamut and modify them to be within gamut. Often, the colors are too saturated and a simple saturation adjustment will do the trick. This is especially true in the blue/purple/red region where it's easy to get too much saturation. You can also adjust the brightness and or the hue as necessary to get the look and feel you are after.

One last comment. The profile is an idealized representation. Your actual TV may differ from it.

Hope this helps.

[Stregga]

First of all Bob, there was no need to appologize, I was simply pointing out the level I am at and my need for further explanation.

Secondly, Thank You for the Extremly detailed explanation and suggestions. I can't wait to try them out. I can't tell you how much I appreciate answers with this level of detail. I truly enjoy learning the inside details to questions like these since they help me to better understand why I am having the problem and how to better react when confronted with them.

I feel I have a better understanding of gamut now. I did a little research online after posting my question which also helped me to better understand your post.

If I may, I would like to ask a few more question.

Whenever the NTSC filters are applied, do they need to be applied to each individual Layer?

SDTV NTSC 16-235 is provided as a way to restrict the luminance range to 16 and 235 (hence the name), it doesn't deal with chroma. It's intended to be used as an aid for conversion to a restricted luminance output space. You can accomplish the same thing with the levels adjustment layer.

Most of the time, it's saturation that causes the problem and the action can help you deal with that. If you use the action, create a "stamp visable" layer at the top of the layer stack and have it as the active layer then run the action.

You stated that the SDTV NTSC 16-235 restricts luminance but doesn't deal with chroma, how can I compensate for the chroma? Or is this another term for saturation? (Never mind, after posting this I found this site which explains this quite extensivly. Check it out and let me know if there is anything further I should know that isn't covered on this site.

http://nemesis.lonestar.org/reference/i ... rimer.html

Since saturation could more likely be the problem you suggested using the action and to create a "stamp visable" layer. This is new to me. What is it and how do I create it, or is the profile conversion you suggested going to make this suggestion void.

Finnaly, I play around quite a bit with layer styles so most of my layouts are in fact grey and I apply layer styles to produce the colors, textures and effects that I am looking for. With that said I have found that some of the effects do not show well on TV. I find this to be true especially with the outer glow. This effect has given me the most trouble since it doesn't seem to show up very well. On larger objects it shows well, but on smaller objects, the all but disappear.

Is this because it is such a light transition between colors (depending on the color selected) or is it more because of the size of the objects? The smaller object are generaly the highligts of my menues when a specific feature is selected ( Play Movie, Scene Selection, etc.).

[Bob]

Whenever the NTSC filters are applied, do they need to be applied to each individual Layer?

If you are referring to the NTSC Colors filter, yes if the layers contain transparency. Filters apply to single layers and you will need to apply it to each layer that has content that shows in the final composite image. However, you wouldn't normally do that. It's a lot easier to do a stamp visable, or merge visible, group the layers and convert to a smart object, or even flatten then apply the filter. However, I don't personally use the NTSC Colors filter. If you are talking about the actions, no. You need to be on the top layer in the layer stack but you apply the action once.

You asked about stamp visible. The keyboard shortcut is ctrl+shift+alt+e and it will do a merge visible and place the result in the current active layer without disturbing the other layers. Normally you would create a new layer and then stamp visible on that. You can combine the two steps by the keyboard shortcut ctrl+shift+alt+n+e. (the ctrl+shift+alt+n creates the new layer and the stamp visable occurs when you press the final e while still holding the other characters). You would normally want the stamp visible layer at the top of the layer stack.

It's difficult to say what's going on with your images using the layer styles without actually seeing them, but I have encounted (infrequently) times in the past when layer style effects were problematic. If in doubt, do a stamp visable. That will take the layer style blending issues out of the equation. You can also convert your layer style effects into regular layers. That makes them a little easier to deal with if you are manually adjusting them, but not all layer style effects convert to individual layers well.

The convert to profile will effectively take a lot of these gamut issues out of the equation. However, it does a merge visible when it converts. If you need to retain the layer structure, be sure to do an image duplicate first so you don't affect your master image file. Keep in mind also that gamut and safe colors are two different concepts and you need to address both. Convert to profile forces in-gamut colors, but it doesn't guarantee NTSC Safe Colors.

That article gives the flavor of what's going on, but it's not strictly correct (see, I told you it was confusing). But, I'm not going to be picky. If it helps understand, great. But, later you might want to look at some additional sites that are more video and/or broadcast oriented. I don't have any particular ones in mind.