Can colour eReaders be used with no frontlight?

[eReader fan]

Hi, I am interested in a colour eInk phone, and because rthat I searched for videos talking about it, and I ended in one where the youtuber said because the method used to achieve colour in Kaleido eInk, it is necessary for the frontlight to be on.

I am not very sure about this, so Icome here to ask to the owners of Hisense colour eInk phones, or the Onyx colour eReaders, to tell to us this detail.

I have severe eyestraining problems, and those includes the frontlight of eReaer devices. I am completelly used to the usage of eInk without light, and can activate it for some moments if it's necesary, but a regular use without light its mandatory in my case.

Anyways, I don't want to buy any colour eInk phones, as the cameras the Hisense colour phones have are very poor, but in the future, for sure.

Waiting for your answers.
Thanks

[Question Mark]

I have a Hisense A5ProCC as well as an Onyx Boox Nova 3 Color. Practically speaking, it is necessary to use the frontlight on both devices as their screens are otherwise quite dark.

If you were outside in direct sunlight or in a very bright room, you could probably get by without using the frontlight. But apart from that scenario, with the technology as it currently stands, the frontlight is necessary.

[Question Mark]

Here is a link to some photos I posted in a thread in these forums soon after I got my A5ProCC: https://www.mobileread.com/forums/sh...&postcount=130

The photos show a colour map with the front light off with some direct sunlight cutting across the screen. You can clearly see how dark is the part of the screen in the shadow.

[Markismus]

Coming out of the dark seasons I quite agree with Question Mark. However, at a lovely picnic last week and with an overhead reading lamp the colors are even better without backlight.

Basically, the Hisense A5 Pro cc is an outdoorsy gadget. There it works even better than those Samsung AMOLED screens. I know, nobody goes outdoors if they can help it, so what's the use, but still: Yes, the screen looks better without backlight _if_ an alternate lightsource is in abundance.

[eReader fan]

It is always interesting when there are two opinions and one contradicts the other.

Mr. Question Mark, are the colours expressed in the same way in the Hisense device than in the Onyx? And another question: when you say the screen is quite dark without the frontlight, do you mean as dark as a b/w eink device, or do you mean even more?

I am taking in consideration both points of view

[Quoth]

Any eink made colour is MUCH darker than the underlying monochrome screen. That's why putting a filter on top of eink to do colour (like filter on top of LCD panels) is a dead end niche technology. If it's saturated colours then it's about 1/6th bright. If pale pastel shades then about 1/2 as bright.

LCDs are transmissive and back lit. You can make the back light as bright as needed. eInk is reflective and opaque. Thus less than 1/2 the brightness for same light. Colourised eink using regular eink under the filter are unusable without a lot of light.
The other issue is that an eink cell is blackish, whiteish and much slower are 14 additional shades of grey. The LCD & OLED easily do 254 levels of grey, black and clear.
You also have lower resolution depending how the colour filter is done. so for a 300 dpi panel either 100 x 300 dpi or 150 x 150 dpi

[Question Mark]

Originally Posted by eReader fan

It is always interesting when there are two opinions and one contradicts the other.

Actually, I thought the opinion of Markismus was in line with my own. Colour eink devices can be used quite readily in direct sunlight or very bright rooms without using the front light. However, with the indoor ambient lighting in most rooms, I find that I need to use the device's front light to read comfortably.

Originally Posted by eReader fan

Mr. Question Mark, are the colours expressed in the same way in the Hisense device than in the Onyx? And another question: when you say the screen is quite dark without the frontlight, do you mean as dark as a b/w eink device, or do you mean even more?

I am taking in consideration both points of view

I find the Hisense A5 Pro CC to be very similar to the Nova 3 Color. The screens are significantly darker than a b/w eink device when the fronlt light is off.

I have attached a couple of pictures of the Nova Pro next to the Nova 3 Color. The front light is off on both devices. In each case, it is the very same book on the very same page. The pictures were taken inside on a sunny afternoon without any artificial light being used in the room. The first picture was taken with a "night view" setting enabled. The second picture was taken with just a regular setting and is a bit blurred.

For some reason, although you can see that it is darker, the N3C does not show up as dark as it is in reality. I could read quite comfortably with the Nova Pro in such lighting. It would be a bit of a strain to read on the N3C without using the front light in such circumstances.