Red background question

[leehljp]

My way of achieving a good photo is to take a hundred picts and hope one is comes out great!:biggrin:

My questions are:
1. What is it about red backgrounds that causes pen (and other items) to appear different in color than they actually are?
2. What can be done or adjusted to have a decent red background yet still allow the correct colors of the items to show forth?

I know the answers will require some techno-speak, but I really would like to understand this. I understand RGB vs CYMK, pigment prime colors vs light prime, and print photos vs screen photos, but the color "red" usually baffles me.

There have been a few red backgrounds posted (and I did one a while back) that greatly alter the colors of the item in it. Red certainly is an enticing background in theory but in actuality I have seen few that allow the true colors to come out. Christmas is coming and probably more will be coming forth.

Recommendations? Thanks.

 

[wdcav1952]

Hank, everyone knows I am photo-challenged, so take this for what it is worth. Put a piece of gray (or white, depending on your software) material in the corner of the background. Take the shot, and used the material to set your color balance. Then, crop the material out of the final photo.

FWIW,

 

[beck3906]

What about taking a photo on a white background, then using a paint tool to "paint" the background red? You should have the correct color item yet have a red color of the hundreds of shades possible.

 

[ranchonodinero]

No facts here, BUT... ...newer digital cameras have better digital processors. I noticed that when I made a switch from an older model to a newer one, there was much less effort required in the way of color correction than the older model. However, take any subject and add a splash of red somewhere-fishing hat or something and it seems to improve the color.

 

[NewLondon88]

My questions are:
1. What is it about red backgrounds that causes pen (and other items) to appear different in color than they actually are?
2. What can be done or adjusted to have a decent red background yet still allow the correct colors of the items to show forth?/quote]

Most photo related equipment works on algorithms that tend to 'normalize' or
'average' colors. (The 18% gray theory says that the average scene
contains colors that when mixed together will equal 18% gray) So when
photo processors, scanners, digital cameras etc. encounter a scene that is
considered 'color failure' then it tries to average out the colors. This is most
often noticed in red scenes, because to average out the color, it
puts in the complimentary color. A blue scene might shift the whites
toward yellow, and green scenes might shift them toward magenta. Those
two aren't normally all that objectionable. And sometimes you DO want
this correction, for things like fluorescent lighting (the light is actually
green, and films capture this) or incandescent (the light is yellow and films
correctly record this)

But a red scene causes a shift toward cyan (blue/green) and when seen
in whites or skin tones, this is off color is immediately noticed. You probably
have old photos of someone wearing a red dress or jacket and
their faces and the background all go a blue/green tint. That's a red color
failure.

(Hank, you're not as likely to find old photos like that. In Japan, proper
printing is more of a point of pride than here in the US, where the average
consumer takes their 'point and shoot' photos to a discount store to have
processed and just got what they got.)

If you can use a gray card as a test, that's great. Take one shot with the
gray card in it, then one without. Use the shot with the gray card to test
your color corrections, and then apply the same corrections to the other
photo. (but that's all after the fact)

Using a white card to set the white balance should help. Some cameras will
allow you to set a white balance as well as black AND gray, giving the
camera software a standard linear neutral from black to white with your
current lighting conditions. In theory, that neutral gradation should be all
the camera needs. But most camera don't have all three. If yours does,
then you're done.

The problem you're most likely to see is that the color shift can happen in
any one of 256 different levels of color, from black to white. This is where
something like Photoshop can help. (after the fact) IF your software allows
you to selectively adjust the colors (highlights, shadows etc) then it should
be easier to correct.

The good part is that the cameras and film are perfectly capable of
capturing the correct color, but most of the time they see an overabundance
of one color as a problem, so they correct for it.
You just need to stop this adjustment before it happens, whether it means
using the gray card or perhaps digging into the software to turn off color
correction. It may be called many things, color correction, compensation,
failure etc. (or others, too) and some cameras allow you to either turn this
off or select whether you need a strong, mild or normal correction.

Sometimes if the camera has a 'Chrome' setting, it may allow you to turn
off color compensation. After all with chrome films (slides) there *is* no
correction in the camera or processing.. it's WYSIWYG.

Hope that wasn't too confusing. (or out of date .. I haven't been in that
business for a while now.. new cameras have come a long way..)

 

[ranchonodinero]

Some of it too can be the computer that is used to view the image-I don't think you can blame it all on the cameras.