Yes, it is possible to stretch a canvas on an already stretched canvas frame. This process is known as re-stretching and involves removing the existing canvas from the frame and replacing it with a new canvas. It is a common practice for artists who want to reuse a frame for a new artwork or for conservators who need to replace a damaged canvas. However, it is important to ensure that the frame is in good condition and suitable for re-stretching before attempting this process. **

It is generally not necessary to tighten a pre-stretched canvas, as it should already be stretched and primed for painting. However, if you notice any sagging or slackness in the canvas, you can use canvas keys (small wooden wedges) to tighten the canvas by inserting them into the corners of the frame and tapping them gently with a hammer. This can help to adjust the tension of the canvas and remove any slackness. Just be careful not to over-tighten the canvas, as this can cause it to warp or crack. **

Yes, it is possible to not erase a pencil on a stretched canvas by using light, gentle strokes when sketching out the initial drawing. This will minimize the visibility of the pencil marks and make it easier to cover them with paint. Additionally, using a kneaded eraser or a soft brush to gently lift off any excess graphite can help to reduce the visibility of the pencil marks without completely erasing them. Finally, using a light-colored ground or underpainting can also help to minimize the appearance of pencil marks on the canvas. **

It depends on the context. If you're asking about which animal I find more fascinating, I would choose the heron for its grace and beauty. However, if the question is about which animal I find more resilient and adaptable, I would choose the cockroach for its ability to survive in various environments. Both animals have unique characteristics that make them interesting in their own way. **

To cover a painted canvas with white, you can use white gesso, which is a primer specifically designed for preparing surfaces for painting. Apply a layer of white gesso over the painted canvas using a brush or a roller, making sure to cover the entire surface evenly. Allow the gesso to dry completely before applying additional layers if needed. Once the gesso is dry, you can paint over it with white acrylic or oil paint to achieve the desired result. **

The white border around a stretched earlobe typically indicates that the skin is being stretched too thin, which can lead to potential issues such as tearing, blowouts, or thinning of the skin. It is a sign that the earlobe may be under too much stress from the stretching process. It is important to listen to your body and give your earlobes time to heal and rest in order to prevent any complications. **

The miracle altar of Heron is a legendary structure said to have been built by the ancient Greek inventor and mathematician, Heron of Alexandria. According to the legend, the altar was designed to produce miraculous effects, such as opening temple doors, making statues move, and producing thunder and lightning. It is believed that the altar used a combination of mechanical and pneumatic principles to create these effects, and it is considered an early example of a primitive form of automation. The exact details of how the altar worked remain a mystery, as the original design has been lost to history. **

There are several measures you can take to protect your fish from herons. One option is to install a protective net over your pond to prevent the heron from accessing the fish. You can also create hiding spots for the fish by adding plants or structures in the pond where they can seek shelter. Additionally, using a motion-activated sprinkler or other deterrents can help scare the heron away from your pond. **