I'm having trouble seeing color differences

Atalanta

Hi, everyone. Thanks for your help previously. 

I'm having trouble seeing color. Specifically, I'm trying to paint a small loaf of bread. The light is above it in a shadow box not unlike those Mark showed how to build. I can't see any difference in the color of the loaf of bread. There is one "wrinkle" in it that casts a shadow, but other than that, I just see a pale tan/yellow. 

But I know when you look at this loaf of bread up close, you see that some parts of it are lighter and others a little darker. But when I sit at my easel and look from four feet away, I can't see any of that. 

Is this a problem with light? Is it too bright? 

I've had trouble balancing lights in my studio and shadow box. That was a difficult exercise for me. I'm using the light temperature/intensity Mark recommended, but my ceiling is only 9 feet. The studio is very bright. But the shadow box also seems very bright. This should even out, right? 

I did put a bit of white on an angled piece of cardboard and placed it in the box and the value seemed to match. But I'm starting to doubt my ability to see these things. I don't wear glasses, I do have floaters in my eye. 

Should I move closer to the shadow box? Should I lower the light everywhere? Is there a good way to actually measure the light in both places so you know you've done it right? I thought about a light meter app for iPhone, but don't know which measurements to match. 

Any help is much appreciated. I'm frustrated and starting to get depressed because I don't seem to be making progress, and only getting more confused. It seems impossible that huge swaths of the composition would be the same color, but that is all I see. 

adridri

Hi. 
For the light intensity I remember someone posted an excel sheet with the necessary lumen on your canvas as fonction of the distance based on the inverse square law of light attenuation. You need about 1000 lumen on the canvas if I recall right, in order to be able to see in your shadows. knowing that  lumens decrease with the square of the distance... Search the forum for that spreadsheet it will tell you how many bulb to put for your bulb to canvas distance.
I personally just use a simple led bulb on the side of my canvas. It's certainly not optimal but does not prevent painting, don't worry if you don't get the perfect setup like in marks videos, you can still paint.
For the balance, if it seemed to match, it should be good enough. 
If you can't see the detail from where you are, you might be too far for the details you try to paint. If you want a detailed view of the loaf of bread, you might consider moving a bit closer. Details smear out as you move away from the subject. Is this you first painting with DMP? 

Most of all don't get depressed. This is going to take time and effort, and setting up the studio isn't easy at all. You'll manage 👍

Best

Adrien 

KingstonFineArt

Lower the room light and see if the set up looks better. 
Posting an image would help.

dencal

Atalanta

Try adding some directional or raking light to create shadows and highlights.
‘If you have lost value discrimination at four feet it sounds like there is too much light and diffuse reflection from adjacent surfaces.

Denis

Still life photography works great with natural light, especially the soft window light that can be used to light the setup or subject from an angle. You can also use soft light in a studio if you are working at night or in a less illuminated location. 

When shooting indoors, you should turn off the normal lights and use only one type of light so you can avoid the colour casts due to lights of various temperatures. Moreover, you do not need to have multiple light sources and have complicated and unpleasant shadows in the frame. 

Direct sunlight can be a bit hard on still life photography, but if you wish to deviate from the fine art look into more of a dramatic mood in the image, or if that is something that will suit the subject of your choice, then you can use this kind of light for still life photography.

https://www.lightstalking.com/still-life-photography-in-five-steps/

Abstraction

Not ignoring all the good advice above, it will all help and hopefully solve your issues and getting the setup to look how you want the finished painting to appear is critical. But once you've done that...

The core of good realism is big tonal statements in right relationship with each other. Details, schmetails. If you capture the main statements you're most of the way there. So... If you just see one colour and one value, put that in, exactly as you see it. I spend half my time in the early stages of a painting with my eyes almost closed looking through my lashes to simplify what I'm looking at. Start there. Pale tan/yellow. Is it all the same value? Block it in. Get the shape right. Get the edges right (hard edges, soft edges, lost edges). It's oil painting - you can come back later and worry about details.

Now*, paint the next biggest difference you see, in order of visual importance. It might not be until much later that you start to notice a slight shift in value that creates undulations or shade or transition into a deeper value...

* If you're precisely following Mark's advice better to consult his instructions than me. I was taught a slightly different process with similar result.

GTO

If you are using a color checker the edge of the color checker should disappear when you compare it to the object.
Once you have the value matched then adjust color.  Ask is your checker more red or more blue or more yellow, etc.  then adjust accordingly.