Wikipedia:Reference desk/Archives/Computing/2020 April 7

= April 7 =

Audio Port Question
I have a Dell Inspiron 3668 desktop computer running Windows 10. In order to be able to view live-streamed events (that can no longer be attended in person due to quarantine), I have bought Logitech Z130 speakers. My question has to do with connecting them to the computer. There are three round audio ports in the back of the computer at the upper left corner, which are pink and green and blue. I was told to connect the audio connection for the speakers to the blue port. Is that correct? Robert McClenon (talk) 03:45, 7 April 2020 (UTC)
 * The relevant article is PC System Design Guide. If your speakers take line-level input, then this is correct advice. Usually, external speakers plug into the "green" headphone jack, which is volume-controlled. Both may work OK for you. It will not damage anything to try each one. Elizium23 (talk) 03:56, 7 April 2020 (UTC)
 * User:Elizium23 - I plugged the speakers into the lime-green jack, and it asks me what device did I plug in. Choices are: Dell Devices; AV410; Headphones; Headphones Medium; Surround Front; Surround Speakers Medium; Surround LFE/Center; Surround Sides.  Robert McClenon (talk) 06:46, 7 April 2020 (UTC)
 * It should be safe to say "Headphones" or "Surround Front", although somewhere you should have an option simply called "Speakers". Elizium23 (talk) 06:55, 7 April 2020 (UTC)
 * Not necessarily: I believe "Speakers" is one of the Windows default options, but drivers can change these to whatever they want. They obviously have the audio adapter driver installed. --47.146.63.87 (talk) 03:59, 8 April 2020 (UTC)
 * You should be able to look up the manual on the Dell website, which will identify all the ports for you. You might even have it already on your computer somewhere. --47.146.63.87 (talk) 03:59, 8 April 2020 (UTC)

Matrix block for image resolution change
I need to convert a 5760x5760 image, in real time, to 3840x3840, on a low-power device. Note that 5760*2/3 = 3840. Will using a matrix to convert 3x3 blocks to 2x2 blocks give good results? ie, we double the linear resolution by splitting each pixel into uniform 2x2 blocks; and then merge 3x3 blocks. Thanks! — Preceding unsigned comment added by 182.156.105.182 (talk) 18:08, 7 April 2020 (UTC)
 * Unless you have specific a priori information about the images, this should be as good as it gets. I just tried it out on an image; while there were small differences with the scaled-down image obtained with the at edges with large brightness gradients, I could not identify them visually. I assume the doubling is a purely virtual operation to explain the idea, because a 3×3 block can directly be downscaled to a 2×2 block without going through an intermediate 6×6 representation. If the algorithm scans in the reading order, it does not need more working storage than one line of pixels plus a few more bytes. Reading input line number 3n the program only needs to store it; while reading line 3n+1 it outputs line number 2n and overwrites the stored line; and while reading line 3n+2 it outputs line number 2n+1.  --Lambiam 22:06, 7 April 2020 (UTC)

Good Monochrome Photographs of ID Papers
I have taken photographs of my ID papers with my cell phone and am trying to print them on a monochrome laser printer. I don't have a color printer and am not planning to buy one. I have the .jpg s of the ID papers on my computer, because I sent them via email from my phone to my email. So far, so good. The pictures look good in color on my computer, but when I print them on a monochrome printer, they come out mostly dark grey. What I would like to do is to lighten them and increase the contrast. Is there a convenient way that I can do that, without getting a color printer? Robert McClenon (talk) 21:04, 7 April 2020 (UTC)
 * Many apps for viewing pictures also have tools for adjusting contrast and brightness, some more sophisticated than others. What OS do you use? Software that works on one may not be available for another. --Lambiam 22:10, 7 April 2020 (UTC)
 * You seem to be using Windows 7. Sorry, can't help you there. --Lambiam 22:13, 7 April 2020 (UTC)
 * I haven't been using Windows 7 since 2017. I am using Windows 10.  Does my user page say that I am using Windows 7?  If so, I should update it.  Robert McClenon (talk) 01:23, 8 April 2020 (UTC)
 * I suspect that you actually have a grayscale laser printer, and not "monochrome" which would surely produce bad results, but I am not aware of any vendors who sell monochrome printers for consumers. Elizium23 (talk) 01:33, 8 April 2020 (UTC)
 * I suggest you download and install GIMP and familiarize yourself with its basic functions. It will go a long way toward the editing you want to do. It is a free and open-source software replacement for Adobe Photoshop. Elizium23 (talk) 01:34, 8 April 2020 (UTC)
 * Microsoft Photos ships with Windows 10 and allows you to make simple adjustments. Open it directly or from the context menu in Windows Explorer (right-click on file, "Edit with Photos"). No offense, but a Web search for something like "windows 10 image adjust contrast" will give tons of results for how to do this. Note the "image" is important because just searching for "adjust contrast" will tend to give pages about adjusting display (monitor) contrast. In general a good first step is a search for   . Also, make sure the print settings aren't what's really to blame here. Go to "Settings" from the print dialogue (the thing that pops up when you go to print) and ensure there isn't something like "High Contrast" turned on. Another tip: if the pictures are low-quality they won't look good printed. You might want to check the settings on your phone camera app to ensure picture quality is maxed. Some phones will let you switch to saving in RAW format rather than JPEG, which also improves quality, although this can make it a bit more complicated to edit the pictures. (There is no standardized "RAW format"; instead there's a bunch of proprietary formats, so whatever you use to edit has to support the format your phone uses.) --47.146.63.87 (talk) 04:22, 8 April 2020 (UTC)
 * If you use GIMP with RAW format photos you may need to load a package named "ufraw-gimp". Not sure how Win does it, I run Linux. Martin of Sheffield (talk) 09:00, 8 April 2020 (UTC)
 * User:Elizium23 - Thank you. I will look into your advice and that of the other editors soon, but not within 24 hours.  I think that I may have been corrected on terminology and will in the future refer to a grayscale printer rather than a monochrome printer.  Either I have been using the term incorrectly for a few decades, or the meanings of the terms has evolved.  Robert McClenon (talk) 22:03, 8 April 2020 (UTC)
 * I have looked at the articles on those terms about printers. It appears that my reference to the printer as monochrome, which is an ambiguous term, was "not incorrect", and I agree that grayscale is more precise.  Thank you for the correction.  Robert McClenon (talk) 22:08, 8 April 2020 (UTC)
 * Just as another option, you may get surprisingly better results from scanning your documents, even with just a plain photocopier, rather than taking a picture of them. Many libraries have scanners or photocopiers (and printers). When you take a photo of a printed object, you introduce a lot of fuzziness that will often "muddy" the picture when you attempt to print it. Giving the documents a scan from a flatbed might be the difference you need. Matt Deres (talk) 14:43, 9 April 2020 (UTC)


 * To print color pictures with a mochrome printer I use Irfan-View's option to convert the pictures to grayscale before printing (Menu Image/Convert to Grayscale). Irfan-View is not really an image editing software but for such simple manipulations it is worlds easier to install and use than Gimp & Co. 2003:F5:6F14:7B00:4999:52FA:30FB:CA06 (talk) 21:55, 13 April 2020 (UTC) Marco PB