Raw B&W versus color conversion

<p>Ok folks, remember I'm still learning and thinking out loud on the way. As some may think,"Gee, we

have to keep this guy from going to the tavern and thinking with a Guiness in his hand."

 

<p>If I understand Bruce Fraser's articles on <a href="http://www.adobe.com/products/photoshop/

cameraraw.html">camera raw</a>, the camera actually records 12-bit grayscale and then convert its to

the color image using the camera's filter and raw processing with ISO and exposure settings. So, why all

the arguments against shooting b&w in the camera instead of shooting color and converting to b&w in

Photoshop? I understand the greater flexibility you get in Photoshop, but if the image is planned to be

b&w through the whole process to print or Web, then why shoot it as color and convert?

 

<p>I must be, as usual, missing something here, but I don't see any gain converting to color in the raw

when you have the same tonal range, one is b&w and one is converted to color. Also, if I still understand it

correctly, then the b&w image is really ISO independent as you compensate with the exposure. At whatever

ISO, with the correct exposure, the sensors still records the same intensity. Where you may have problems

pushing or pulling film, digital doesn't, so you can shoot whatever ISO gives you the shutter speed or

aperture you want or need.

 

<p>Or so the thinking goes so far. I've appreciated everyone's help trying to understand the basic

concepts to digital capture, production and printing.

The light hitting the sensor elements has already gone through red, green, and blue filters, so it's already "colorized". The in-camera B&W conversion is nothing more than the same process you do in Photoshop, just with a fixed set of parameters.

 

Cheers,

 

Geoff S.

"Where you may have problems pushing or pulling film, digital doesn't, so you can shoot whatever ISO gives you the shutter speed or aperture you want or need."

 

Changing the sensitivity of a solid-state imaging sensor is done by changing the gain in the amplifiers that convert the very small signal from a sensor-element into a voltage that's large enough to be digitized. As you "turn up the volume" to get more sensitivity you increase the noise in the digitized signal.

 

TANSTAAFL

 

Cheers,

 

Geoff S.

Don't think of the image in the camera as grayscale and it may help you to understand. The camera uses a color filter array on top of the sensor and depending on the pixel location either red, green or blue light is received and stored. This means that while your camera may be 8mp for example, there are 4mp of green information, and 2 each of red and blue. The full 8mp three color image has to be interpolated from this sampling so technically the red and blue channels have a lower resolving power than green.

 

If you use the cameras B&W mode it uses a set blending of the channels and produces the grayscale image. Doing it to the RGB image in photoshop or a similar program later lets you duplicate the effects of various color filters or play with the channel mixer to find the exact blend of the red, green and blue scene information you want. I find the results from that can be tweaked to be much more pleasing than the usually stale B&W output from most digital cameras.

 

Don't discount the effect ISO has on the image, the sensor is not recording the same intensity at a higher ISO with a shorter shutter speed (and same aperture). The sensor is in fact receiving fewer photons and as a result has less signal. This signal must be boosted (by changing the gain on the amplifier as mentioned). The sensor has a base noise characteristic as well which also gets boosted in the process so the higher you crank the ISO, the lower your signal to noise ratio.

Thanks, I'll keep reading, doing and learning.

<p>Ok, after morning coffee and rereading the paper. If I understand it, again likely with

some to a lot of misunderstanding, the raw file has the grayscale value for each pixel with

the specific color filter. For display purposes (camera and computer) and the output jpeg

file (if chosen), it generates the image with that and the other metadata (picture style,

white balance, etc.). With the raw file you can adjust all the parameters in the metadata to

output an image.

 

<p>If it uses the individual pixel information and its neighbors to generate a color image,

a black and white version is a conversion of that into grayscale? So it's the same image,

one in color and one in grayscale. The advantage to shooting color and converting to b&w

are the tools in the raw converter or Photoshop to undo the color into grayscale.

 

<p>Looking at the results of the <a href="http://www.wsrphoto.com/

c5dblog15.html">grayscale test</a> I did there are minute visual differences in the

images (converted raw files using same method). I was looking at the push/pull effect at

that time. The question is the balance for what you want from the image and accetable

noise.

 

Again thanks.

I am not going to try and even address the technical part of the above scenario, but..........."...The advantage to shooting color and converting to b&w are the tools in the raw converter or Photoshop to undo the color into grayscale..."...is a monstrous understatement. It IS all the difference in the world. A good start in explaining this to you is a book, Black and White Digital Photography by Michael Freeman. Also, as good as Bruce Fraser's articles on the web are, you really need to read it all in a particular order...his book, Camera RAW with Adobe Photoshop CS2, will help you better grasp the whole issue.

Interesting statement, ""...is a monstrous understatement. It IS all the difference in the

world." I think b&w film photographers might have an issue there with this, but it's not a

film versus digital discussion, they're simply different paths to capture and produce

images. My interest is understanding b&w (monochrome) from the camera, because it

changes your view of looking and seeing, and then capturing an image. It's simply

personal choice of the tools we use.

 

Is it fair to say all the b&w's images on your Website are color conversions? Or not? I'm

curious. They're interesting. I didn't see any explanation of your capture and production

process or methods.

actually, all of my website "proper" (ie the Photoblog is actually hosted at "blogspot.com") Black and Whites is B&W film...scanned. It would be only in the Photoblog that you would find converted digital color to b&w...and even then only back a couple months. And this is mainly due to me never liking my color to b&w conversions before say August of 2006. And the reason for that is that I had never explored the use of modifying color hue and saturation when converting to black and white. It makes a world of difference. Think of color contrast filters that film b&w users put on their lenses to darken or lighten certain colors. That's what you can do in the RAW converter or in Photoshop proper...only much much more (I can darken Puce now if I want......heh) to make your b&w's so much more.

 

The "grayscale" conversion method, either in the camera or in photoshop are programmed in at one certain blend of rgb. In RAW and PS you have limitless control..........LIMITLESS!

 

Being a film photographer first, and mostly in black and white, your comment "...My interest is understanding b&w (monochrome) from the camera, because it changes your view of looking and seeing, and then capturing an image. It's simply personal choice of the tools we use..." is to be completely understood. But having been a film black and white shooter, I had no choice but to see the actual scene in black and white. I had no image on the camera to look at. My brain actually had to be taught to see in black and white.

 

So, when I picked up a digital cam, and when I made the conscious decision while taking a pic that I wanted the end result in black and white, I thought that using the black and white in the camera would be a good idea also. Problem is, what ever that blend of rgb to black and white formula my camera used, was not what I had spent 30 some years developing in my head. Nor was the photoshop version of desaturate or convert to grayscale. They were wearily bland compared to what I was use to getting.

 

It probably took me a good 6 months of reading and experimenting with conversions before I found that i could get what I wanted by messing with the colors while doing the conversion. Of course once I had that down, modifying curves during the conversion was the final tweak I wanted. I don't really know if my color to black and white conversions look like my film black and white. And I don't think they do. Because while I was experimenting, I found that I actually had more control of the image than I ever had with a straight film black and white thing. This has caused me to actually see black and white differently while shooting. I'm actually modifying my brains way of seeing black and white while shooting. I actually think turning on the black and white mode in the camera might hinder me now adays. i say might, because i've haven't turned on that black and white camera mode in over a year now.

 

Now, maybe black and white in the camera and color converted to black and white in photoshop using the grayscale convert are the same.........something tells me they are not. Mainly because, in my case, Canon used their formula of conversion in my camera, and Adobe used their formula of conversion in my computer. Neither of which I like. i like MY method of conversion............heh.

 

So, if nothing else, it's a matter of me being able to make the final image more of what I want it to be by converting it later. The "canned" camera and photoshop conversions just don't make it for me.

A 40 year addiction to Kodachrome (starting from an early age) prevents me from seeing in black and white.

Thanks for the answer about your images. It helps me understand. While others like shooting

color and converting to b&w when they see an image they like, I like b&w film and from my

camera, it's a challenge to know and simply the workflow. That's the beauty of all the tools

you have these days, you can pick what works for you to produce the images you like or

want.

oh....I still shoot B&W film.......got 6 rolls right now that need developing.

 

As far as Kodachrome, charles.........when they stopped making Kodachrome 25 (never really did like K64 all that much), I tried getting use to Velvia, but it never worked........so I quit using slides. Good thing Agfa Ultra, Portra Vivid Color and then Ultra Color came along in color negatives.....kept me happy until digital color came along.

For me, the answer is really simple.<p>

 

If you shoot black and white with the camera in b&w mode, you are letting <i>the camera</i> make the initial decisions as to what the b&w looks like.<p>If the end use of the image is to be b&w, what that b&w image looks like should be <i>your</i> decision, based on how you see the shot...not based on the camera's algorithm.<p>Cameras, chips, sensors, and software don't think...photographers do.

Shoot RAW plus JPEG in B&W mode. You'll get the instant B&W JPEGs you want, but if you don't like them you'll have the full color info in the RAW file to play with.