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Re: [NH] PNG -- good idea or otherwise

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  • David
    Hi most of the new browsers no problem ,alot of the older browsers may not sure how many there is left usually gifs are better on B/W TEXT and jpgs are
    Message 1 of 14 , Jan 28, 2003
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      Hi
      most of the new browsers no problem ,alot of the older browsers may not sure
      how many there is left
      usually gifs are better on B/W TEXT and jpgs are better on full color .
      THANKYOU DAVE
      ----- Original Message -----
      From: "Fay" <feigh@...>
      To: <ntb-html@yahoogroups.com>
      Sent: Tuesday, January 28, 2003 8:31 PM
      Subject: [NH] PNG -- good idea or otherwise


      > Hello people,
      > I messed up my first web pages by using jpgs where I should have used
      gifs.
      > I did change a lot of them, but there are some left.
      > I've made some pngs, and they're smaller than gifs.
      > What I've read at http://www.libpng.org/pub/png/
      > sounds positive.
      > I'm not sure, though, whether all browsers would read them, or if there's
      > anything else I haven't considered.
      > Should I continue to replace jpgs with gifs, or go straight to png?
      >
      >
      >
      >
      > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
      >
      >
    • Peter Steeper
      Hi Fay, I usually use JPEGs for photographs and GIFs for logos and animated graphics. JPEG means Joint Photographic Experts Group and it was developed to
      Message 2 of 14 , Jan 28, 2003
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        Hi Fay,
        I usually use JPEGs for photographs and GIFs for logos and animated graphics. JPEG means Joint Photographic Experts Group and it was developed to provide good and flexible compression for photos.

        If you have Photoshop with Imageready, you can try various types of file formats and levels of compression on your images. Just open an image in Photoshop, go to the file menu and select Save for Web. This will open your image in Image Ready. There are several options for file types, compression levels and you can get an estimate of download times at various connection speeds. This is very handy for optimizing images.

        In Photoshop Colour Settings make sure your RGB colour space is set to sRGB or you will get colour shifts when your images are displayed in a web browser. The default colour space for web browsers is sRGB.

        I did some testing of PNG graphics and wrote an article about it for my photo club. You can find the article here:
        http://www.photoguild.ns.ca/about/webuse.html

        For photographs I found that PNG graphics were considerably larger than a JPEG. I did not try PNG for logos (I'm a photographer). PNG graphics do have a size advantage when you are including information about the colour space that was used. Since this is a rarely used I opted to use JPEG images for the photos on the web site.

        There are also samples of the effects of different levels of compression on the images. You will be able compare the quality of the image vs. download time.

        If you post your URL I can check your images.


        Peter Steeper
        Webmaster
        Photographic Guild of Nova Scotia
        www.photoguild.ns.ca

        Halifax, Nova Scotia
        Canada


        ----- Original Message -----
        From: Fay
        To: ntb-html@yahoogroups.com
        Sent: Tuesday, January 28, 2003 5:31 AM
        Subject: [NH] PNG -- good idea or otherwise


        Hello people,
        I messed up my first web pages by using jpgs where I should have used gifs.
        I did change a lot of them, but there are some left.
        I've made some pngs, and they're smaller than gifs.
        What I've read at http://www.libpng.org/pub/png/
        sounds positive.
        I'm not sure, though, whether all browsers would read them, or if there's
        anything else I haven't considered.
        Should I continue to replace jpgs with gifs, or go straight to png?


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      • Fay
        Thank you Peter. I ll go and read your page now. My site is http://www.netspace.net.au/~feigh/ It s just a family and friends site.
        Message 3 of 14 , Jan 28, 2003
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          Thank you Peter. I'll go and read your page now. My site is
          http://www.netspace.net.au/~feigh/
          It's just a family and friends site.
        • Fay
          Peter, your site is about high quality photographs. I m concerned about screen shots and work from paint programs, using only a few colours. If these are saved
          Message 4 of 14 , Jan 28, 2003
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            Peter, your site is about high quality photographs.
            I'm concerned about screen shots and work from paint programs, using only a
            few colours.
            If these are saved as jpgs they "bleed".
            I didn't see this until someone pointed it out, but they look pretty awful.
            Photos, on the other hand, look great as jpgs.
          • Fay
            Thank you, David. It was about older browsers that I was concerned.
            Message 5 of 14 , Jan 28, 2003
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              Thank you, David. It was about older browsers that I was concerned.
            • hugo_paulissen <h.paulissen@facburfdcw.u
              ... using only a ... pretty awful. Fay, Peter, et al As a rule of thumb you could say that images with less than 256 colours can be exported to gif without
              Message 6 of 14 , Jan 28, 2003
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                --- In ntb-html@yahoogroups.com, "Fay" <feigh@i...> wrote:
                > Peter, your site is about high quality photographs.
                > I'm concerned about screen shots and work from paint programs,
                using only a
                > few colours.
                > If these are saved as jpgs they "bleed".
                > I didn't see this until someone pointed it out, but they look
                pretty awful.

                Fay, Peter, et al

                As a rule of thumb you could say that images with less than 256
                colours can be exported to gif without problems. They will look
                sharp - and before converting the image you could try to reduce the
                number of colors as well, to see the effect of the final image. In
                your image program there will be an option to count all the colors in
                your image.

                JPG's can be saved in many different ways. Personally I only work
                with the highest quality settings (and I keep the original images as
                well). JPG images are calculated, derived, from the information in
                the image itself, pixel by pixel - so there is always some
                information lost. The better your settings, the better the final
                result will be... But for screendumps, on-screen texts etc. I only
                convert to gif.

                FWIW,

                Hugo
              • John Zeman <john041650@yahoo.com>
                Here s my 2 cents worth on this subject: Gif s are limited color images. They can contain up to, but not exceeding 256 different colors. Therefore they should
                Message 7 of 14 , Jan 28, 2003
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                  Here's my 2 cents worth on this subject:

                  Gif's are limited color images. They can contain up to, but not exceeding 256 different colors. Therefore they should be used as the format for images with few colors, such as most custom created graphics, logos, etc. Custom graphics with well over 256 colors (which happens when gradients are used) should be saved as a jpg. Photos should also be saved in the jpeg (jpg) format. I generally use a medium to high compression (in the Photoshop jpg30 to 50 range). Also, an image should only be saved as a jpg one time as distortion is introduced each time it's saved as a jpg. I've found an exception to that is when I start with a very large jpg image, and want to end up with a much smaller jpg image.. The distortion in the original jpg disappears (to the naked eye anyway) when the image is reduced in size.

                  I have to admit that so far, I have only used the png format sparingly and haven't come to any definite conclusions about it yet.

                  John



                  --- In ntb-html@yahoogroups.com, "Fay" <feigh@i...> wrote:
                  > Thank you, David. It was about older browsers that I was concerned.
                • John Zeman <john041650@yahoo.com>
                  Ahh, once again I see I should have checked the message board just before posting.. Hugo beat me to the punch, but I see he s saying the same things I did for
                  Message 8 of 14 , Jan 28, 2003
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                    Ahh, once again I see I should have checked the message board just before posting.. Hugo beat me to the punch, but I see he's saying the same things I did for the most part..

                    John


                    --- In ntb-html@yahoogroups.com, "hugo_paulissen <h.paulissen@f...>" <h.paulissen@f...> wrote:
                    > --- In ntb-html@yahoogroups.com, "Fay" <feigh@i...> wrote:
                    > > Peter, your site is about high quality photographs.
                    > > I'm concerned about screen shots and work from paint programs,
                    > using only a
                    > > few colours.
                    > > If these are saved as jpgs they "bleed".
                    > > I didn't see this until someone pointed it out, but they look
                    > pretty awful.
                    >
                    > Fay, Peter, et al
                    >
                    > As a rule of thumb you could say that images with less than 256
                    > colours can be exported to gif without problems. They will look
                    > sharp - and before converting the image you could try to reduce the
                    > number of colors as well, to see the effect of the final image. In
                    > your image program there will be an option to count all the colors in
                    > your image.
                    >
                    > JPG's can be saved in many different ways. Personally I only work
                    > with the highest quality settings (and I keep the original images as
                    > well). JPG images are calculated, derived, from the information in
                    > the image itself, pixel by pixel - so there is always some
                    > information lost. The better your settings, the better the final
                    > result will be... But for screendumps, on-screen texts etc. I only
                    > convert to gif.
                    >
                    > FWIW,
                    >
                    > Hugo
                  • Don Passenger
                    PNG s are supported in the latest release of the three most significant browsers. They offer several advantages over .gif and .jpg images I suppose: lossless
                    Message 9 of 14 , Jan 28, 2003
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                      PNG's are supported in the latest release of the three most significant
                      browsers.

                      They offer several advantages over .gif and .jpg images I suppose:
                      lossless compression (unlike jpg which is lossy)
                      interlacing (unlike .gif I believe)

                      like .gif and .jpg-2000 (a format now available and supported by Adobe
                      Photoshop and Photoshop Elements), png allows transparency. It's
                      transparency is actually superior to that of .gif however, because it is
                      variable, allowing partial transparency. You may also get better
                      anti-aliasing on curves because of partial transparency.

                      Because of gamma correction, colors may remain truer from platform/device to
                      another as well.

                      It lacks animation I believe -- which leaves you with .gif (or flash or
                      mpegs etc for non-static images).

                      Even the PNG sites will tell you that for a finished product which is a full
                      color photo, jpg is likely to render an acceptable product at a smaller file
                      size.

                      PNG gives up backwards compatibility (even though newer browsers support it,
                      older ones don't). I think this is daily becoming less significant.

                      For some reason, png has not overwhelmed the world of image display, maybe
                      because until recently backwards compatibility was such an issue. But if
                      you like them and understand how to use them (if you save a true color line
                      art image without reducing colors you get a big file for example), there is
                      no reason not to venture into the realm of png.

                      Don

                      p.s. This really is HTML relevant, but not notetab relevant ... but I
                      responded anyway. If I should not have, I apologize.


                      ----- Original Message -----
                      From: "Fay" <feigh@...>
                      To: <ntb-html@yahoogroups.com>
                      Sent: Tuesday, January 28, 2003 4:31 AM
                      Subject: [NH] PNG -- good idea or otherwise


                      > Hello people,
                      > I messed up my first web pages by using jpgs where I should have used
                      gifs.
                      > I did change a lot of them, but there are some left.
                      > I've made some pngs, and they're smaller than gifs.
                      > What I've read at http://www.libpng.org/pub/png/
                      > sounds positive.
                      > I'm not sure, though, whether all browsers would read them, or if there's
                      > anything else I haven't considered.
                      > Should I continue to replace jpgs with gifs, or go straight to png?
                      >
                      >
                      >
                      >
                      > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
                      >
                      >
                    • Don Passenger
                      Making a good jpg is always a trade off. You can save it at greater or lesser levels of compression. (A good program for this by the way is Eric Fookes easy
                      Message 10 of 14 , Jan 28, 2003
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                        Making a good jpg is always a trade off. You can save it at greater or
                        lesser levels of compression. (A good program for this by the way is Eric
                        Fookes easy thumbnails available at http://www.notetab.com which is
                        freeware).

                        http://www.netspace.net.au/~feigh/oe_options_general.jpg looks fine to me.
                        I understand the concept and get exactly what you are saying with it. I am
                        not looking at it as art, I am trying to determine appropriate settings. I
                        would never study it close enough to wonder if there was a slight bleed.
                        You are trying too hard. Lower your standards, life is more fun that way.

                        Don

                        ----- Original Message -----
                        From: "Fay" <feigh@...>
                        To: <ntb-html@yahoogroups.com>
                        Sent: Tuesday, January 28, 2003 4:03 PM
                        Subject: Re: [NH] PNG -- good idea or otherwise


                        > Thanks hrs,
                        > You said:
                        > <<I don't understand the need to change the graphics file type. >>
                        > My pictures were "bleeding," as would happen if you wet a printed page.
                        > The ones that looked worst were shots of icons or dialogue boxes.
                        > On http://www.netspace.net.au/~feigh/outlook_express.html there are bad
                        > ones.
                        > The second picture from the top has little red squares representing
                        postage
                        > stamps. Because I used jpg, they have a haze of pink where they've been
                        > smoothed into the white instead of having a hard edge.
                      • Fay
                        Thanks hrs, You said:
                        Message 11 of 14 , Jan 28, 2003
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                          Thanks hrs,
                          You said:
                          <<I don't understand the need to change the graphics file type. >>
                          My pictures were "bleeding," as would happen if you wet a printed page.
                          The ones that looked worst were shots of icons or dialogue boxes.
                          On http://www.netspace.net.au/~feigh/outlook_express.html there are bad
                          ones.
                          The second picture from the top has little red squares representing postage
                          stamps. Because I used jpg, they have a haze of pink where they've been
                          smoothed into the white instead of having a hard edge.
                          Gif saves don't do this. I've been replacing jpgs with gifs, but recently
                          saw that pngs are smaller.
                          Then I wondered if all browsers could read pngs. I have NS4 for checking,
                          but thought it might be sensible to ask before I remade lots of pictures.
                        • Fay
                          Thanks Don.
                          Message 12 of 14 , Jan 28, 2003
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                            Thanks Don. <big smile>
                          • John Zeman <john041650@yahoo.com>
                            ... Fay I m afraid you lost me here. I looked at your sample images, which appear to be Outlook Express dialog boxes, and for those I would use the gif
                            Message 13 of 14 , Jan 28, 2003
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                              --- In ntb-html@yahoogroups.com, "Fay" <feigh@i...> wrote:
                              > My pictures were "bleeding," as would happen if you wet a printed page.
                              > The ones that looked worst were shots of icons or dialogue boxes.
                              > On http://www.netspace.net.au/~feigh/outlook_express.html there are bad
                              > ones.


                              Fay I'm afraid you lost me here. I looked at your sample images, which appear to be Outlook Express dialog boxes, and for those I would use the gif format.. I've done similar screen dump saves many times with excellent results when they're saved as a gif. Usually much better results and smaller files sizes, than I'd get when they're saved as a jpg.

                              One of the options you should have in saving a gif, is how many colors to allow it to use, did you save them at 256 colors? In the link below all your images are now jpg format, do you still have any uploaded as gifs? If you do, we could take a look at those gifs and maybe see why they do not display the way you want.

                              I almost never print web pages, and I have to admit I've never heard of wet printing before..

                              If this thread continues, perhaps we should move it to off topic as it really has nothing to do with NoteTab.

                              John
                            • Peter Steeper
                              Hi Fay and Group, The guys are right. I forgot to mention that GIFs use indexed colour and support a maximum of 256 colours. Since images of dialog boxes have
                              Message 14 of 14 , Jan 28, 2003
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                                Hi Fay and Group,

                                The guys are right. I forgot to mention that GIFs use indexed colour and support a maximum of 256 colours. Since images of dialog boxes have a limited range of colours GIFs are a great format for this purpose. Because of the way JPEGs are compressed you can get splotchy looking images of logos and line art such as the dialog box images on your web site..

                                I checked your web site and experimented with one of the images. "select_stationery_box.jpg"
                                As a JPEG the file size is 38,050 bytes. As a GIF the size is 30,819 and 30,032 as a PNG-8.
                                I would use the GIF format as it is well suited to the type of graphics you are using on your web site and you won't have to worry about compatibility and it is smaller than the JPEGs.

                                -Peter
                                ----- Original Message -----
                                From: loro
                                To: ntb-html@yahoogroups.com
                                Sent: Tuesday, January 28, 2003 9:17 PM
                                Subject: Re: [NH] PNG -- good idea or otherwise


                                Fay wrote:
                                > I've made some pngs, and they're smaller than
                                > gifs. What I've read at
                                > http://www.libpng.org/pub/png/sounds positive. I'm
                                > not sure, though, whether all browsers would read
                                > them, or if there's anything else I haven't
                                > considered. Should I continue to replace jpgs with
                                > gifs, or go straight to png?




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