13 replies to this topic

[sligeach]

I have recently moved to a new lab and one of the things that we dont have here is a small polaroid like printer which you can use to print of images of your gels (western blots and PCR). In my previous lab i found such a printer very handy as you could print of the picture from your blot or pcr and then attach it to your lab book. The size of picture is relatively small only about a fifth of the size of an a4 page and the image used to be printed out on a plastic polaroid type material. Ive tried searching the web but i cant seem to find something similar so im hoping that someone here might know what im talking about and suggest possible models to buy. thanks

[Trof]

We have a termal printer (Mitsubishi P91E) but it has far worse dynamic range than normal laser printer. Also the photopaper is smooth and it's difficult to glue it into notebook, unsticks after some time.

To print image of gel on normal laser printer you need just simple image editor like Irfan View (free), you take your raw image, crop only the parts you want (no need to print empty parts of gel besides or below bands), invert! (this is important because it turns mostly black picture into a mostly white with black bands, saves printer toner) and in the print dialog change printing size on the paper (I usually use 1cm per well, that more than enough), set printer to the highest quality (or if it has that option to 'Photo' setting), print.
You will get small image (exact size you want), perfectly dynamic bands, and if you want you can even play with contrast and gamma setting in Irfan to make the bands more distinct if they are weak. It's on normal printer paper, so it glues in fine.
I don't use the thermal printer anymore. (also printing one thermal image is 10x more expensive (the paper is expensive)  than printing one A4 page in copy center, so the real price of small image printed on A4 paper is even far less).

Example of such print (this print is bigger because it's a restriction, and I like it bigger, but there really is no limit how small you want to print it), those fainter bands won't be visible well in thermoprint.

[mdfenko]

and thermal prints tend to fade (especially when taped).

here is a google search for "snapshot printers"

here is advice from consumer reports

this is the canon selphy

and these are kodak easyshare printers

to name a few.

Edited by mdfenko, 27 November 2012 - 08:47 AM.

[hobglobin]

I think one advantage or even need (next to the many disadvantages of these thermal prints) is that you have some protection against falsification of the gel images, as they usually print the "live signal" from the video capture input. All the other printers print saved files that might have already be worked on with Photoshop/Gimp et al. So some labs with ISO lab standards might need this (I'm not so familiar with these standards), to fulfil some protection against fraud standards.

[mdfenko]

unless the thermal printer is integral with the image capture device (camera) then any type of printer can be substituted. when the printing occurs is not a function of the printer but, rather, of the imaging device.

[pito]

I find it pretty weird that you would buy a special printer for something like that.
We just print it out on a normal printer.
And to save paper, we simple print it on paper that has allready some text on it (on the other side) and that you dont need anymore.
Or we print more things on 1 piece of paper..

The printers you speak about: they are expensive and also not really environmentalfriendly.

[Trof]

Yes, our thermal printer was able to print from Scion imaging software, that had among many the ability to make an integration of several images (I usualy made 40), the result had no background noise and it looked very pretty. Even this or any edited image opened in Scion could be printed

[phage434]

The thermal printer paper is also not particularly stable.  The image will degrade over a year or so.  Laser printer output is far more robust.

[Trof]

phage434: Probably not these thermal papers (those used in shops definitely do), because I have images from our printer from the time I started in our lab, from 2005 and they are still as new. I also have my very first PCR image somewhere from 2003 and it's still fine. Although the marker I used to label it is way off.

[mdfenko]

Trof, on 27 November 2012 - 12:36 PM, said:

Yes, our thermal printer was able to print from Scion imaging software, that had among many the ability to make an integration of several images (I usualy made 40), the result had no background noise and it looked very pretty. Even this or any edited image opened in Scion could be printed

is the printer "thermal" or "thermal transfer"?

thermal transfer is stable. it melts dye and puts it onto the paper (some work with ribbons and direct contact, others, like dye sublimation printers, spray the dye vapor onto the paper). it works best with coated papers (just as photo printers do).

thermal printers print onto coated papers with a heated printhead, turning the heat-sensitive coating black.

similar to thermal printers are (were?) electrostatic printers. the one with which i'm familiar used silvered paper. the images from this printer were relatively stable.

Edited by mdfenko, 28 November 2012 - 06:51 AM.

[hobglobin]

mdfenko, on 27 November 2012 - 09:15 AM, said:

unless the thermal printer is integral with the image capture device (camera) then any type of printer can be substituted. when the printing occurs is not a function of the printer but, rather, of the imaging device.

I guess I confused it with out old system which had no computer but a CCD camera connected to the video grabber card...with USB it's different then of course...
The fading I also can observe but I always thought it's related to exposure to light, as the ones not in my lab journal but flying around on the desk are much more faded and yellowish (it's one of these Mitsubishi thermal printers).

[mdfenko]

hobglobin, on 28 November 2012 - 08:03 AM, said:

I guess I confused it with out old system which had no computer but a CCD camera connected to the video grabber card...with USB it's different then of course...

not so different. the video grabber cards connected to the printer with either a parallel or serial connector.  you could just as easily attach an epson or okidata (or other) dot matrix impact printer (may require some software tweaking but might not, epson printer language was pretty standard).

Quote

The fading I also can observe but I always thought it's related to exposure to light, as the ones not in my lab journal but flying around on the desk are much more faded and yellowish (it's one of these Mitsubishi thermal printers).

light and heat do cause fading and background darkening. i've seen images on taped sections of thermal prints disappear and the paper not darken in that area. maybe there is a reaction of the paper's coating with the glue of the tape?

[Trof]

mdfenko, on 28 November 2012 - 06:50 AM, said:

is the printer "thermal" or "thermal transfer"?

I have no idea. It's described everywhere as "thermal printer" nothing else.

[mdfenko]

Trof, on 29 November 2012 - 04:04 PM, said:

I have no idea. It's described everywhere as "thermal printer" nothing else.

is the paper heat sensitive? if so then it is a "thermal" printer.