Wireless Device Tone Chart
- Instructions -

File Type:  JPEG image file.  Approximate size is 9KB. There is no embedded color profile.

File Extension:  *.jpg
Purpose:  Used to analyze the ability of a handheld wireless device to display the full range of tones, ranging from solid black to solid white.

---

Background

Compared to today’s professional computer monitors, mobile device displays are rudimentary.  They have a very limited color gamut and are also limited in their ability to display the full range of tones, from black to white.  Regardless of whether you are going to display color or Black and White images on your wireless device, you will want to know how well your device can reproduce tone.

To use the tone chart, shown in Figure 1, download it to your computer, load it onto your wireless device, examine it, and see how many individual squares you can distinguish. The more squares you can distinguish, the more tones the device can reproduce.  If the squares begin to merge into one solid mass, then the device is limited in its ability to display that range of tones.

Figure 2 shows a cell phone with the Tone Chart displayed on its internal display.  When the chart is viewed on this particular cell phone, one can see that the phone does a reasonably good job of displaying blacks. However, light tones quickly get blown out to solid white. What does this mean? It means this cell phone handles the medium and dark tones well, but images with light and white tones quickly burn out. So images with lots of light tones will not display properly on this particular cell phone.
 

Download the File

Click the Download button.  Follow your web browser's instructions for saving this file onto your computer.  Make sure you remember where you saved it.  The file name is tz-device-tone-chart.jpg.  If you rename the file, do not change the extension.  Leave it jpg.  After downloading, if prompted to Open the file or Close the download dialog box, close the dialog box.
 

Load The File Onto Wireless Device

Loading image files onto a mobile device is particular to the device.  Therefore, the instructions below are general in nature and describe the three most common methods.

• Once the file has been downloaded onto your computer, open your email software on your computer and create an email.  Address the email to your wireless email account, attach the JPEG file to the email and send it.  On your wireless device, open the email and save the file.
• Using a flash memory card that is compatible with both your computer and your wireless device, save the file from your computer to the memory card, insert the memory card into your device, and then save the file to your mobile device.
• Some wireless carriers offer special accounts where you can upload your file from your computer and then download the file onto your device.

 

Using the Grid

1. Go to your wireless devices display settings and select the Tone Chart as the image to be displayed.
2. Once the Tone Chart is displayed, examine it, and see how many individual squares you can distinguish.  The tone chart has seven rows.  The top six rows have eight squares each.  The bottom row has four tone squares and four color squares.  The more squares you can distinguish, the more tones the device can reproduce.  If the squares begin to merge into one solid mass, then the device is limited in its ability to display that range of tones.
3. With this information, you should be able to tell if your display is better at displaying one end of the tonal range over the other. This will let you know what kinds of images are appropriate for your particular device.