Image of a Longer 4K mono resin 3D printer

Check out the Longer Orange 4K Mono Resin 3D Printer on Longer’s Website.

This printer is a unit. It is all metal construction except for the acrylic shield and the resin vat inside. Everything else is metal. It is super solid and that makes it heavy. It is 11 and a half kilos or about 25 pounds, which is nice.

I don’t know about you, but when I get a tool, unless it’s meant to be light, I like that tool to have weight to it. That makes the tool feels like it’s quality, and this feels like a quality printer. The Longer has a 5.5-inch LCD 4K screen in it.

5.5 inch LCD screen on the Longer 4K mono

If you are brand new to resin printing, The way it works is we have a UV light source that is down inside the base. It shines up through an LCD screen.

UV light shining through the LCD screen on Longer 4K mono resin printer.

The LCD screen will display images on it to mask off areas. So anywhere that we want to harden the resin, we want the light to come through and that is clear on the screen. Anywhere we don’t want the resin to harden is opaque, and that is how we cure the resin.

LCD screen displaying image to mask off areas for resin curing.

And we do that layer by layer by layer and build it up. The 4K resolution is in reference to the screen itself. That is how many pixels we have inside of the 5.5-inch LCD.


Printing area is 120 by 68 millimeters with 190 millimeters of height. So, this is on the small side of resin printers. However, for me, that’s not a big deal because I’m typically printing small things like miniatures or rings and jewelry that I’m going metal cast small stuff.

Image showing the print bed of a Longer 4K mono with 120x68mm build volume

I don’t typically resin print large items. If I’m going to print a large item, I’ll usually do that on my FDM printer. If you are looking for a resin printer for things like cosplay where you’re going to do big full-face shields or helmets, you probably will want to look at a bigger printer.

Large FDM printed mask.

One of the things that I really like about this printer is it just works out of the box. I don’t know about you, but for me, I absolutely love it when a product just works, and I don’t have to mess with it. I had this set up and printing in about five minutes, literally from out of the box to adding resin and starting a print was five minutes, which I think is fan fantastic, especially if this is your first resin printer. That’s a fantastic quality. You don’t have to spend a bunch of time sort of tweaking and getting it set up.


The Z-axis has two solid aluminum bars on the side of the Z axis and a metal and an aluminum plate on the back. This Z axis is rock solid. There is no play side to side or front to back. This has dual linear rails in the Z axis, so there is no way for the Z carriage to get cockeyed. It will only go straight up and down.

The solidly built z-axis on a Longer 4K mono printer

If you’re not familiar with linear rails, they are one of the best methods for getting precision in CNC machining. In terms of resolution, like I said, it is a 4K screen and the print area is 120 by 68. The Z axis layer height, so the thickness of the layers you can print are from 0.01mm to 0.10mm. That’s one 100th of a millimeter up to 0.1 or one 10th of a millimeter in thickness.

For me, I’ve been printing at 0.05 millimeters since I’ve had this and fantastic results. On the front we have this small LCD screen. And I’ll be honest, this is one of the downsides for me, this screen is a little small.

The touch screen controller on the Longer 4K mono

I would like to see a larger screen. My old printer has a much larger screen on it which makes it just a little bit easier to use, especially for people like me.

Touchscreen controller for an Elegoo Mars

I’m getting a little bit older. Eyesight’s not as good as it used to be without glasses. Needing to come out here and then put some glasses on to mess with the printer is a little bit of an annoyance, but it’s not a deal breaker.


On the side, we’ve got the USB port, which is a great place for it because my old printer was on the back, I ended up needing an extension cable to run around to the front to be able to plug in the USB without searching for it or knocking the printer over.

Image showing the front and side of a Longer 4K mono printer

And on the back, we’ve got the power connector and the tiniest little power switch. Look at this ridiculously small little power switch! But it works. It’s a little silly having such a small power switch.

An image of a person holding their index finger next to the small power switch on a Longer 4k mono printer

For those of you who are new to 3D printing with resin, your home or consumer version 3D printers have screen. However, some printers have RGB screens in them. And the way an RGB screen works is we have a red, a green, and a blue layer that are all sandwiched between a couple other pieces on the LCD, which means there are multiple layers that the UV light must shine through to expose the resin.

image showing the multiple layers that make up an LCD screen

What that means is the amount of light that gets through is not as bright or as powerful, and it takes longer to cure the resin with the UV light. On a mono printer, the screen has one layer that the light has to shine through, so it basically reduces the amount of diffusion by two thirds, meaning we need less time to cure the resin in a mono printer resulting in faster print times.


So that’s a big upside for me. I’ve basically cut my print times by about two thirds. A lot of manufacturers say a mono prints three times faster. Take that with a grain of salt. Your results may vary depending on the resin you’re using.


We do need to talk about the elephant in the room, though. This printer is a little bit more on the expensive side for the print area that you get. However, I will say that the quality of the printer and the fact that it just works, every single time I’ve printed with it is worth the money, in my opinion. Now I, have had failed prints, but they were my fault because I had screwed up settings in Chitubox. So that was on me.

The printer has performed flawlessly every single time I hit print. Again, the Longer just works. I’ve had. No problems with bed adhesion. I’ve had no layer shifting, nothing. It just works.

Another minor annoyance and it’s not a big deal, is that on my old printer, the resin vat had sort of an indentation that it would sit down in, so it was easier to index and then you could lock it in place with the screws.

The Longer doesn’t have any sort of indentation, so you must fiddle with it for a little bit to get it screwed in. But honestly for me, I’m not changing resin vats out, I put it in once and I’m done, and only take it out to clean it or change resin and that’s it.

Let’s look at some of the items I’ve printed with the Longer. For all the items printed in this review I used Longer’s Transparent Green resin.

Image of a vampire lord bust model 3d printed in transparent green resin using a Longer 4K mono printer

This is the Vampire Lord model that came pre-supported from longer and it turned out well. There were some issues as I missed removing some supports on the chest before I cured the print, so you’ll see there is some scarring.

Image showing a macro shot of the chin and chest area of a model that has scarring.
An image showing the 3d printed vampire lord bust after it has been primed with black paint.

This is Ursalox, Stargazer. This is a miniature bust from which song Miniatures. You can purchase a copy of this STL for this model here.  This model has a lot of detail, which is what I was looking for, to showcase the resin printer’s abilities. There’s fur, there’s bone, lots of tiny details. I primed both models in black to show more of the detail. And then I got a little carried away and decided to paint Ursalox. I haven’t painted in over a year and I couldn’t help myself, so I threw on some color, I did some washes, and in about an hour and a half I had a fantastic looking result. I am super happy with how this turned out.

Image of a fully painted fantasy figure bust. The bust is a humanoid bear wearing a decorative skull crown and wearing spinal cords as necklaces.

I am super happy with the quality, and I’m going to say it again. I know it sound like a broken record, but it just works. And for me, that is invaluable in a tool because when I’m in creative mode and I’m trying to make stuff. I don’t want to have to spend a bunch of time fooling around with the tools, getting them to work.


Would I buy the longer for me? Yes. Because again, I’m doing a lot of smaller items. I don’t need a huge build volume. And the bigger build volume you get, the more resin you use and, well, the rein isn’t cheap, so I’m happy with the build volume for this. If you’re looking for a bigger build volume, you’re going to need a different printer.


But if like me, you’re doing small things like miniatures or things like that, I can absolutely without reservation recommend the longer. Check out the Longer Orange 4K Mono Resin 3D Printer on Longer’s Website!