TL;DR: The black-and-white flash you see when PicPak changes photos is a screen refresh. E-ink moves physical pigment particles to form an image, and every so often it flips the whole screen through black and white to clear out any leftover traces from the last picture. It's completely normal, it keeps your images sharp, and it's a sign the screen is working exactly as designed.
Why does my PicPak flash black and white when it changes photos?
That flash is called a screen refresh, and it's a normal part of how e-ink works. Unlike a phone screen that redraws instantly, e-ink forms an image by physically moving tiny pigment particles into place. When it switches to a new photo, it briefly flips the entire screen through black and white to reset every particle and wipe away any faint remnants of the previous image. The flash lasts around 15 seconds, then your new photo settles in clean and crisp. Nothing is wrong. The screen is just clearing its slate.
What is screen refresh, exactly?
E-ink images are made of millions of microscopic particles that get nudged to the surface by a small electric charge. Once they're in place, they stay put with no power, which is why PicPak can hold an image for ages on a single charge. The catch is that moving those particles to a brand new arrangement works best if the screen first resets to a clean state. The quick black, white, and sometimes inverted flash is that reset happening. Think of it like wiping a whiteboard fully clean before writing something new, rather than writing over faint old marks.
What is ghosting, and is the flash preventing it?
Yes. Ghosting is the faint shadow of a previous image that can linger if a new one is drawn straight on top without a reset. You may have seen it on an e-reader, a pale trace of the last page behind the current one. The full black-and-white refresh is exactly what prevents that. By flipping every particle through a clean cycle, PicPak makes sure your new photo shows up with no leftover haze from the one before. So the flash you see isn't a flaw. It's the screen actively protecting image quality.
Is the flashing bad for the screen?
Not at all. Refreshing is the intended, healthy way for e-ink to update, and the screen is built to do it for years. It also uses almost no power, since e-ink only draws energy in the moment it changes the image and none at all while displaying one. That's the whole reason a PicPak can run for around a year on a charge. The brief flash is a tiny, occasional event in exchange for a screen that otherwise sits there using nothing.
Why doesn't my phone or TV do this?
Because they make images in a completely different way. A phone or TV is lit from behind and redraws its whole screen many times a second using light, so there's nothing physical to reset. E-ink uses pigment particles and reflected light instead, which is what gives it that calm, paper-like quality and lets it hold an image without power. The trade-off for those benefits is the occasional refresh flash. If you're curious about the deeper difference, our guide on e-ink vs LCD breaks down exactly how the two technologies work.
The short version
The flash is a feature, not a fault. It's how e-ink resets itself to keep your photos clean and ghost-free, it costs almost no power, and it's part of what makes the screen feel like paper rather than a glowing device. Once you know what it is, it stops looking like a glitch and starts looking like the screen doing its job.
