A STARTLING AND PERPLEXING visual phenomenon I've observed

First view the diagram I drew and try to make sense of it.

The characteristic colors are, from low to high frequency: red, orange, yellow, green, cyan, blue, violet. Sufficient differences in frequency give rise to a difference in perceived hue; the just noticeable difference in wavelength varies from about 1 nm in the blue-green and yellow wavelengths, to 10 nm and more in the red and blue.

As you see in the picture, when the character suddenly wakes up, the iris is completely dilated. The iris is like a muscular curtain that opens and closes. In the dark, it becomes completely dilated (relaxed); the opposite is true when in heavy light. In very low light levels, vision is scotopic: light is detected by rod cells of the retina.

Rods are maximally sensitive to wavelengths near 500 nm, and play little, if any, role in color vision. In brighter light, such as daylight, vision is photopic: light is detected by cone cells which are responsible for color vision. Cones are sensitive to a range of wavelengths, but are most sensitive to wavelengths near 555 nm (green is around 520–570 nm). Between these regions, mesopic vision comes into play and both rods and cones provide signals to the retinal ganglion cells. The shift in color perception from dim light to daylight gives rise to differences known as the Purkinje effect - which is what happened to you.

An object may be viewed under various conditions. For example, it may be illuminated by sunlight, the light of a fire, or a harsh electric light. In all of these situations, human vision perceives that the object has the same color: an apple always appears red, whether viewed at night or during the day. On the other hand, a camera with no adjustment for light may register the apple as having varying color. This feature of the visual system is called chromatic adaptation, or color constancy; when the correction occurs in a camera it is referred to as white balance.

Chromatic adaptation is one aspect of vision that may fool someone into observing a color-based optical illusion, such as the same color illusion.

Though the human visual system generally does maintain constant perceived color under different lighting, there are situations where the relative brightness of two different stimuli will appear reversed at different illuminance levels. For example, the bright yellow petals of flowers will appear dark compared to the green leaves in dim light while the opposite is true during the day. This is known as the Purkinje effect, and arises because the peak sensitivity of the human eye shifts toward the blue end of the spectrum at lower light levels.

Lewis, first let me thank you for your admirable effort to explain the unusual phenomenon I experienced.  If you sense that my use of the word "effort" suggests that I'm not satisfied with your explanation, you are correct. 

But now that I've been doing some reading, and some hard thinking, about the matter, I do have an explanation of my own. 

But first let me administer, in one swift blow, the coup de grace to your invocation of the Purkinje Effect as the explanation.  As you point out, the Purkinje Effect shifts the sensitivity of the retina to the blue end of the spectrum.  So if we have a red object and green object side by side, in normal light the red object will be brighter than the green, but in dim light the reverse will be true, as the red object will become darker.  But when we try to apply this Purkinje Effect to the digital clock situation we don't find that at all.   In dim light  (or total darkness) the traditional digital clock, with red numerals, remains as red and as visible as it was in normal light.  If the Purkinje Effect was altering the digital clock with green numerals, it would alter the one with red numerals even more.  Since the clock with red numerals remains unchanged, the Purkinje Effect cannot be responsible for what's occurring with the digital clocks.

Now here's my explanation.  First let's imagine the following situation:  We have two digital clocks, side by side, one with red numerals, one with green.  We close our eyes and simultaneously turn off all the lights in the room and are in total darkness, except for the light emitted by the two clocks.  Now, if  we open our eyes two seconds later, the red numerals will appear red and the green numerals green.  However, if we keep our eyes closed until full dark adaptation occurs and then open them, the red numerals will still appear red, but the green will appear absolutely white.  Here's my explanation:  the rods start to become active with darkness, and simultaneously the cones sensitive to medium and short wavelength light become inactive.  Rods have two features relevant to the digital clock puzzle: 1)They don't register color, only the presence or absence of light, and 2)They don't perceive red or long wavelength light.  That's why human operations that require full dark adaptation but also the ability to read are conducted in red light or with goggles that only permit red light to enter the eyes; the presence of only red light allows full dark adaptation, but abundant red light will permit someone to read or do other activities that require bright illumination.  So the reason that the red numerals appear red is that the cones for red light are still fully active and thus perceive the red numerals as they would in a normally lighted room.  However, the green numerals are perceived only by the rods.  (The cones that perceive the wavelength of green light have been rendered inactive by dark adaptation, so they are not involved in the perception of the green numerals at this later point in the experiment, versus when we opened our eyes after two seconds.)  But since rods only perceive the presence of light, not its color, the green light of the numerals is perceived as white, an absence of color. 

Now, let's turn to the situation I described in my original post, where I asked the question, Why do green OBJECTS appear green, but the green LIGHT appears white?  Evidently, the cones for medium and short wavelengths become active again very quickly, and the brighter the light, the faster the reactivation.  So, when I awaken fully dark adapted, in the area of the room OPPOSITE to where the light bulb is, it's so dim that green OBJECTS are just dark, so little light is coming from them. (And, of course, the green numerals are white.) But now, as I get up and cross the room, towards the light, two things are happening. 1)In those few seconds, the cones sensitive to green light are swiftly reactivating, and 2)The light from the bulb is now sufficient to reflect enough off the linoleum to make it green instead of just dark.  Hence I perceive the floor as green, while a few seconds before I perceived the green numerals as white. If instead of getting up, I remain in bed (and thus am not moving closer to the light) with my eyes open, the green numerals will stay white for a considerable time (several minutes), since the reactivation of the green-perceiving cones will take longer in the very dim light on this side of the room, far from the light bulb.  And green objects near me will just appear dark, since so little light is being reflected.

That explanation seems to account for everything I observed, in a nice, logical way.