Call: 919-841-3132

Archive for the Seascapes Painting Classes Category

Sea Shells Painting.

Sea Shells Painting Class Acrylics and Oils.

Sea Shells-Painting Class acrylics oils

Sea Shells-Painting Class acrylics oils

Taught by Artist Clina Polloni.

This seascape of shells was created for the painting classes, beautiful colors of shells on the sand under a blue ocean sky. 

Supply: This painting can be done in 2 medias, Oil Paintings or Acrylics:

Acrylics: You can buy them at Michael’s or Hobby Lobby. There are many brands of acrylic paintings that I have tested but the one that I like the most is SOHO, Urban Artistic Acrylic: Excellent paintings, sold at more reasonable price by Jerry’s Arterama. 3060 Wake Forest Road, Raleigh, NC 27609. (919) 876-6610. Also, Kaleidoscope Artist’s Value is good.

Oil Paintings: You can buy them at Michael’s, Hobby Lobby, but again the most affordable ones are at Jerry’s Arterama and their brand is LUKAS.

Canvas: 11″x14″

Colors:

  1. Titanium White
  2. Yellow Ochre
  3. Flesh or Portrait Pink or Pale Pink
  4. Cerulean Blue
  5. Ultramarine Blue
  6. Magenta
  7. Dioxazine Purple
  8. Burnt Sienna
  9. Raw Umber
  10. Payne Gray
  11. Ivory Black

There are many affordable brushes in the market:
Walmart: FolkArt, Gold Taklon, fine details and shading.
Hobby Lobby: The Fine Touch.
Michael’s: 10pc “Artist’s Loft” white synthetic brushes.
Jerry’s Arterama: Pro Stroke-Power Creative, fine and medium brushes.

For Oil paintings, the best media is Refined Linseed Oil with Turpernoi. To clean the brushes Turpernoi. Glass container to mix media.

Easel (a simple table metal easel is fine).

Paper towel.

Paper/plastic plate and glass. SOHO has a very reasonable paper palette at Jerry’s Arterama.

#paintingclassesnc #seascape #seashellspainting #littleartgallerync #wakeforestnc #clinapolloni #thecottonco #oilsclasses #acrylicsclasses #clinapolloniart #clinahpolloni #artistachilena #northcarolinaartist

You can learn and enjoy to do this painting in the painting classes:
https://clinapolloni.com/painting-classes/

Call Clina: 919-841-3132

Email: clinapolloni@gmail.com

The “Sea Shells” painting is © Clina Polloni.

Visit Clina Polloni Art Studio and Gallery.
13 Garner Road, Franklinton NC 27527.
Take a drive to the beautiful country of North Carolina. Only half an hour from downtown Raleigh.

Fishing Village of NC July 19-23 Painting Class.

Painting Class-Fishing Village in North Carolina

Painting Class-Fishing Village in North Carolina

Learn to paint a seascape of an old fishing town in North Carolina.

“Fishing Village of NC” July 19-23. Acrylics or oils, private and group painting classes by appointment. Taught by Clina Polloni. Call 919-841-3132 or email clinapolloni@gmail.com.

#paintingclasses #fishingvillage #littleartgallerync #seascape #wakeforestnc #thecottonco #oilsclasses #acrylicsclasses #clinapolloniart #clinahpolloni #artistachilena #northcarolinaartist

$30.00 per person for 3 hours. You have the option of learning the painting of the week or selecting a painting from https://clinapolloni.com/painting-classes/.

At The Little Art Gallery, inside The Cotton Company, located in the historical downtown of Wake Forest NC. 306 S. White Street, Wake Forest, NC 27587.

Supply: https://clinapolloni.com/fishing-village-of-nc/

Sailing to the Sunset July 5-9 Painting Class.

Painting Class acrylics oils-Sailing to the Sunset Seascape

Painting Class acrylics oils-Sailing to the Sunset Seascape

Learn to paint a sunset seascape Sailing to the Sunset.

July 5-9. Acrylics or oils, private and group painting classes by appointment. Taught by Clina Polloni with social distance. Call 919-841-3132 or email clinapolloni@gmail.com.

#paintingclasses #seascape #oceansunset #sailboat #littleartgallerync #wakeforestnc #thecottonco #oilsclasses #acrylicsclasses #clinapolloniart #clinahpolloni #artistachilena #northcarolinaartist #socialdistancing

$30.00 per person for 3 hours. You have the option of learning the painting of the week or selecting a painting from https://clinapolloni.com/painting-classes/.

At The Little Art Gallery, inside The Cotton Company, located in the historical downtown of Wake Forest NC. 306 S. White Street, Wake Forest, NC 27587.

Supply: https://clinapolloni.com/sailing-to-the-south-africa-sea/

Sea Dunes with Sail Boat May 17 to 31 Painting Class.

Painting Class acrylics oils-Sea Dunes with Sail Boat

Painting Class acrylics oils-Sea Dunes with Sail Boat.

Learn to paint a seascape with sea dunes and reflections of a boat in the ocean.

May 17 to 21, 24 to 28 and 31. Acrylics or Oils painting classes taught by Clina Polloni with social distance.

$30.00 per person for 3 hours. Private and group classes. You have the option of learning the painting of the week or selecting a painting from https://clinapolloni.com/painting-classes/.

Please make appointment, we have a limited capacity to respect social distancing. Call 919-841-3132 or email clinapolloni@gmail.com.

At The Cotton Company located in the historical downtown of Wake Forest NC. 306 S. White Street, Wake Forest, NC 27587. Or Clina Polloni Art Studio: 13 Garner Road, Franklinton NC 27525.

#paintingclasses #seadunes #sailboat #littleartgallery #socialdistancing #wakeforestnc #thecottonco #oilsclasses #acrylicsclasses #clinapolloniart #clinahpolloni #artistachilena #northcarolinaartist

Supply: https://clinapolloni.com/sea-dunes-with-sail-boat/

Palm Tree at The Beach Painting

How to Paint A Palm Tree at The Beach.

Seascape-Palm Tree at the Beach

Seascape-Palm Tree at the Beach

Seascape Painting Classes. Acrylics and Oils.

Taught by Clina Polloni with social distance.

Learn to paint a palm tree at the beach seascape with clear waters of the ocean, is a simple and charming painting for a person that is starting to paint.

Follow the instructions:

  1. Start by drawing the horizon line, mountains, ocean and beach, finally the palm tree.
  2. Do an acrylic under-paint, using Cerulean Blue and Titanium White with water for the sky, mountains and ocean. For the beach Yellow Ochre and Titanium White. Be sure to impregnate all the surface of the canvas.
  3. Continue with acrylics or oils. Paint the sky, ocean, mountains and beach.
  4. Finally paint the palm tree on the top.
  5. Sign your painting.

Supply: This painting can be done in 2 medias, Oil Paintings or Acrylics:

Seascape-Palm Tree-how to paint

Seascape-Palm Tree-how to paint

Acrylics: You can buy them at Michael’s or Hobby Lobby. There are many brands of acrylic paintings that I have tested but the one that I like the most is SOHO, Urban Artistic Acrylic: Excellent paintings, sold at more reasonable price by Jerry’s Arterama. 3060 Wake Forest Road, Raleigh, NC 27609. (919) 876-6610.

Oil Paintings: You can buy them at Michael’s, Hobby Lobby, but again the most affordable ones are at Jerry’s Arterama and their brand is LUKAS.

Canvas: 11″x14″

Colors:

  1. Titanium White
  2. Cadmium Yellow Light
  3. Yellow Ochre
  4. Portrait Pink or Pale Pink
  5. Sap Green
  6. Cerulean Blue
  7. Ultramarine Blue
  8. Van Dick Brown

Brushes, multi-purpose, polyvalent. There is a 10pc “Artist’s Loft” that provides most of the brushes for the beginning or the Pro Stroke-Power Creative Mark of Jerry’s Arterama. Also, Wal-Mart has some fine and medium gold taklon brushes.

For Oil paintings, the best media is Refined Linseed Oil with Refined Turpentine. To clean the brushes Turpernoi. I have some glass containers to mix media.

Easel (a simple table metal easel is fine).

Paper towel, Pencil to draw.

Plastic plate to mix colors or a Paper Palette. SOHO has a very reasonable paper palette at Jerry’s Arterama.

You can learn and enjoy to do this painting in the painting classes >>
Call Clina: 919-841-3132
Email: clinapolloni@gmail.com

The Palm Tree at The Beach Painting and instructions are © Clina Polloni.

Visit Clina Polloni Art Studio and Gallery.
13 Garner Road, Franklinton NC 27525.
Take a drive to the beautiful country of North Carolina. Only half an hour from downtown Raleigh.

 Serving Raleigh, Cary, Durham, Wake Forest, Franklinton and The Triangle Are of North Carolina.
Member of The Franklin County Art Council and Wake Forest Guild of Artists, of North Carolina.

White House in the Ocean Seascape

Tiny White House in the Ocean

White House in the Ocean Seascape.

White House in the Ocean Seascape.

Painting Class Taught by Artist Clina Polloni.

Learn to paint a tiny house on the beach with white picket fence. Is a simple and charming painting for a person that is starting to paint.

This seascape painting was created for the painting classes, you can do it at home or come to the painting classes when the Coronavirus is over.

Acrylic under-paint: Cerulean Blue and Titanium White with water for the sky and ocean. For the beach Yellow Ochre and Titanium White. Be sure to impregnate all the surface of the canvas.

Supply: This painting can be done in 2 medias, Oil Paintings or Acrylics:

Acrylics: You can buy them at Michael’s or Hobby Lobby. There are many brands of acrylic paintings that I have tested but the one that I like the most is SOHO, Urban Artistic Acrylic: Excellent paintings, sold at more reasonable price by Jerry’s Arterama. 3060 Wake Forest Road, Raleigh, NC 27609. (919) 876-6610.

Oil Paintings: You can buy them at Michael’s, Hobby Lobby, but again the most affordable ones are at Jerry’s Arterama and their brand is LUKAS.

Canvas: 11″x 14″

Colors:

  1. Titanium White
  2. Cadmium Yellow Light
  3. Cadmium Yellow Medium
  4. Yellow Ochre
  5. Flesh, Portrait Pink or Pale Pink
  6. Sap Green
  7. Cerulean Blue
  8. Ultramarine Blue
  9. Dioxazine Purple
  10. Burnt Sienna
  11. Burnt Umber or a Van Dyck Brown

Brushes, multi-purpose, polyvalent. There is a 10pc “Artist’s Loft” that provides most of the brushes for the beginning or the Pro Stroke-Power Creative Mark of Jerry’s Arterama. Also, Wal-Mart has some fine and medium gold taklon brushes. 1 White Bristle #3.

For Oil paintings, the best media is Refined Linseed Oil with Refined Turpentine. To clean the brushes Turpernoi. I have some glass containers to mix media.

Easel (a simple table metal easel is fine).

Paper towel, Pencil to draw.

Plastic/paper plate and glass. SOHO has a very reasonable paper palette at Jerry’s Arterama.

Painting Class acrylics oils-White House in the Ocean

Painting Class acrylics oils-White House in the Ocean

You can learn and enjoy to do this painting in the painting classes >>

#paintingclasses #littleartgallerync #houseintheocean #seascape #thecottonco #oilsclasses #acrylicsclasses #clinapolloniart #clinahpolloni #artistachilena #northcarolinaartist #wakeforestnc

Call Clina: 919-841-3132
Email: clinapolloni@gmail.com

The White House in the Ocean Painting and instructions are © Clina Polloni.

Visit Clina Polloni Art Studio and Gallery.
13 Garner Road, Franklinton NC 27525.
Take a drive to the beautiful country of North Carolina. Only half an hour from downtown Raleigh. 

Serving Raleigh, Cary, Durham, Wake Forest, Franklinton and The Triangle Are of North Carolina.
Member of The Franklin County Art Council and Wake Forest Guild of Artists, of North Carolina.

Palm Tree at The Beach Painting

Painting Class Taught by Artist Clina Polloni.

Learn to paint a palm tree at the beach with clear waters of the ocean, is a simple and charming painting for a person that is starting to paint.

Seascape-Palm Tree at the Beach

Seascape-Palm Tree at the Beach

This seascape painting was created for the painting classes, you can do it at home or come to the painting classes when the Coronavirus is over.

Supply: This painting can be done in 2 medias, Oil Paintings or Acrylics:

Acrylics: You can buy them at Michael’s or Hobby Lobby. There are many brands of acrylic paintings that I have tested but the one that I like the most is SOHO, Urban Artistic Acrylic: Excellent paintings, sold at a more reasonable price by Jerry’s Arterama. 3060 Wake Forest Road, Raleigh, NC 27609. (919) 876-6610.

Oil Paintings: You can buy them at Michael’s, Hobby Lobby, but again the most affordable ones are at Jerry’s Arterama and their brand is LUKAS.

Canvas: 11″x 14″

Seascape-Palm Tree-how to paint

Seascape-Palm Tree-how to paint

Under-paint Color: Acrylic washed of Cerulean Blue, Yellow Ochre and Titanium White.

Colors:

  1. Titanium White
  2. Cadmium Yellow Light
  3. Yellow Ochre
  4. Portrait Pink or Pale Pink
  5. Sap Green
  6. Emerald Green
  7. Cerulean Blue
  8. Ultramarine Blue
  9. Burnt Sienna
  10. Burnt Umber or Van Dick Brown
  11. Ivory Black

There are many affordable brushes in the market:
Walmart: FolkArt, Gold Taklon, fine details and shading corners detail.
Michael’s: Artist’s Loft, white synthetic brushes.
Jerry’s Arterama: Pro Stroke-Power Creative, fine and medium brushes.
1 White Bristle #2.

Sienna Hughes-Palm Tree-Painting Classes Acrylics Oils.

Sienna Hughes-Palm Tree-Painting Classes Acrylics Oils.

Black fine point Sharpie.

For Oil paintings, the best media is Refined Linseed Oil with Refined Turpentine. To clean the brushes Turpernoi. I have some glass containers to mix media.

Easel (a simple table metal easel is fine).

Paper towel, Pencil to draw.

Paper/plastic plate and glass. SOHO has a very reasonable paper palette at Jerry’s Arterama.

#paintingclasses #seascape #palmtree #beach #littleartgallerync #wakeforestnc #thecottonco #oilsclasses #acrylicsclasses #clinapolloniart #clinahpolloni #artistachilena #northcarolinaartist #socialdistancing

You can learn and enjoy to do this painting in the painting classes >>

Call Clina: 919-841-3132
Email: clinapolloni@gmail.com

Palm Tree Painting Classes.

Palm Tree Painting Classes.

The Palm Tree at The Beach Painting is © Clina Polloni.

Visit Clina Polloni Art Studio and Gallery.
13 Garner Road, Franklinton NC 27525.
Take a drive to the beautiful country of North Carolina. Only half an hour from downtown Raleigh.

 Serving Raleigh, Cary, Durham, Wake Forest, Franklinton and The Triangle Are of North Carolina.
Member of The Franklin County Art Council and Wake Forest Guild of Artists, of North Carolina.

Pigeon Point Lighthouse Painting.

Painting Class Taught by Artist Clina Polloni.

Pigeon Point Lighthouse Painting.

Pigeon Point Lighthouse Painting

Pigeon Point Lighthouse Painting

This seascape of a lighthouse was created for the painting classes, is a simple and charming painting for a person that is starting to paint.

Painting Class Supply:

This painting can be done in 2 medias, Oil Paintings or Acrylics.

Acrylics: You can buy them at Michael’s or Hobby Lobby. There are many brands of acrylic paintings that I have tested but the one that I like the most is SOHO, Urban Artistic Acrylic: Excellent paintings, sold at more reasonable price by Jerry’s Arterama. 3060 Wake Forest Road, Raleigh, NC 27609. (919) 876-6610.

Oil Paintings: You can buy them at Michael’s, Hobby Lobby, but again the most affordable ones are at Jerry’s Arterama and their brand is LUKAS.

Canvas: 11″ x 14″

Pigeon Point Lighthouse Under-paint

Pigeon Point Lighthouse Under-paint

Colors:

  1. Titanium White
  2. Cadmium Yellow Light
  3. Cadmium Yellow Medium
  4. Yellow Ochre
  5. Cadmium Red Medium or Carmine
  6. Alizarin Crimson
  7. Sap Green
  8. Cerulean Blue
  9. Ultramarine Blue
  10. Dioxazine Purple
  11. Burnt Sienna
  12. Burnt Umber or Van Dick Brown
  13. Ivory Black

There are many affordable brushes in the market:

Harper Clarkson-2024 AWARDS-Painting Classes.

Harper Clarkson-2024 AWARDS-Painting Classes.

Hobby Lobby: The Fine Touch.
Walmart: FolkArt, Gold Taklon, fine details and shading corners detail.
Michael’s: Artist’s Loft, white synthetic brushes.
Jerry’s Arterama: Pro Stroke-Power Creative, fine and medium brushes.

Black fine point Sharpie.

For Oil paintings, the best media is Refined Linseed Oil with Turpernoi. To clean the brushes Turpernoi. Glass container to mix media, I have some containers in the studio.

Easel (a simple table metal easel is fine).

Paper towel.

Paper/plastic plate and glass. SOHO has a very reasonable paper palette at Jerry’s Arterama.

Painting Class acrylics oils-Pigeon Point Lighthouse

Painting Class acrylics oils-Pigeon Point Lighthouse

You can learn and enjoy to do this painting in the painting classes >>

Call Clina: 919-841-3132

Email: clinapolloni@gmail.com 

#paintingclasses #seascape #lighthousepainting #littleartgallerync #wakeforestnc #thecottonco #oilsclasses #acrylicsclasses #clinapolloniart #clinahpolloni #artistachilena #northcarolinaartist #socialdistancing

Visit Clina Polloni Art Studio and Gallery.
13 Garner Road, Franklinton NC 27525.
Take a drive to the beautiful country of North Carolina. Only half an hour from downtown Raleigh.

 Serving Raleigh, Cary, Louisburg, Wake Forest, Franklinton and The Triangle Are of North Carolina.
Member of The Franklin County Art Council and
 Wake Forest Guild of Artists, of North Carolina.

Students showing their paintings:

Fishing Village of NC

Painting Class Taught by Artist Clina Polloni.

Fishing Village of NC Seascape.

Fishing Village Seascape

This Seascape was created for the painting classes, is a simple and charming painting for a person that is starting to paint. The painting is about a fishing town in North Carolina, in colonial times.

Supply: This painting can be done in 2 medias, Oil Paintings or Acrylics:

Acrylics: You can buy them at Michael’s or Hobby Lobby. There are many brands of acrylic paintings that I have tested but the one that I like the most is SOHO, Urban Artistic Acrylic: Excellent paintings, sold at more reasonable price by Jerry’s Arterama. 3060 Wake Forest Road, Raleigh, NC 27609. (919) 876-6610. Also, Kaleidoscope Artist’s Value is good.

Oil Paintings: You can buy them at Michael’s, Hobby Lobby, but again the most affordable ones are at Jerry’s Arterama and their brand is LUKAS.

Canvas: 11″ x 14″

Colors:

  1. Titanium White
  2. Cadmium Yellow Light
  3. Yellow Ochre
  4. Flesh, Portrait Pink or Pale Pink
  5. Cadmium Red Medium
  6. Alizarin Crimson or Rose Madder
  7. Sap Green
  8. Greenish Umber or Deep Green
  9. Payne’s Gray
  10. Cerulean Blue
  11. Ultramarine Blue
  12. Burnt Sienna
  13. Van Dyck Brown or Raw Umber or Burnt Umber
  14. Ivory Black

There are many affordable brushes in the market:
Walmart: FolkArt, Gold Taklon, fine details and shading corners detail.
Michael’s: Artist’s Loft, white synthetic brushes.
Jerry’s Arterama: Pro Stroke-Power Creative, fine and medium brushes.
1 White Bristle #3.
Black fine point Sharpie.
For Oil paintings, the best media is Refined Linseed Oil with Turpernoi. To clean the brushes Turpernoi. Glass container to mix media, I have some containers in the studio.
Easel (a simple table metal easel is fine).
Paper towel.
Plastic/Paper plate and glass. SOHO has a very reasonable paper palette at Jerry’s Arterama.

You can learn and enjoy to do this painting in the painting classes:

https://clinapolloni.com/painting-classes/

Painting Class-Fishing Village in North Carolina

Painting Class-Fishing Village in North Carolina

Call Clina: 919-841-3132
Email: clinapolloni@gmail.com
Contact Clina >>

#paintingclasses #fishingvillage #littleartgallerync #seascape #wakeforestnc #thecottonco #oilsclasses #acrylicsclasses #clinapolloniart #clinahpolloni #artistachilena #northcarolinaartist

Visit Clina Polloni Art Studio and Gallery.
13 Garner Road, Franklinton NC 27525.
Take a drive to the beautiful country of North Carolina. Only half an hour from downtown Raleigh.

 Serving Raleigh, Cary, Durham, Wake Forest, Franklinton and The Triangle Are of North Carolina.
Member of The Franklin County Art Council and
 Wake Forest Guild of Artists, of North Carolina.

Tree in a Field of Lavender Painting.

Tree in a Field of Lavender.

Painting Class Taught by Artist Clina Polloni.

Tree in a Field of Lavender Painting

Tree in a Field of Lavender Painting

A tree in the front of mountains with a field of purple lavenders. This painting was inspired by the mountains and landscape of North Carolina. A simple painting created for the painting classes.

Instructions:

  1. Draw tree and mountains.
  2. The best and easier way of painting this landscape is by doing an under-paint with acrylics using: Titanium White, Cerulean Blue and Ivory Black. Paint the entire canvas with a mixture of Titanium White and Cerulean Blue. Outline tree with black.
  3. Now you can start the painting. It can be done with oils or acrylics. First is the mountains, second the grass, walkway and flowers. Finally, the leaves of the tree with shades of greens for light and shading.

Supply: This painting can be done in 2 medias, Oil Paintings or Acrylics:

Acrylics: You can buy them at Michael’s or Hobby Lobby. There are many brands of acrylic paintings that I have tested but the one that I like the most is SOHO, Urban Artistic Acrylic: Excellent paintings, sold at more reasonable price by Jerry’s Arterama. 3060 Wake Forest Road, Raleigh, NC 27609. (919) 876-6610.

Oil Paintings: You can buy them at Michael’s, Hobby Lobby, but again the most affordable ones are at Jerry’s Arterama and their brand is LUKAS.

Tree in a Field of Lavender-Starting to Paint

Tree in a Field of Lavender-Starting to Paint

Canvas: 11”x 14”

Colors:

  1. Titanium White
  2. Cadmium Yellow Light
  3. Cadmium Yellow Medium
  4. Cerulean Blue
  5. Ultramarine Blue
  6. Sap Green
  7. Yellow Ochre
  8. Raw Sienna
  9. Burnt Sienna
  10. Dioxazine Purple
  11. Burnt Umber or Van Dyck
  12. Ivory Black

There are many affordable brushes in the market:
Walmart: FolkArt, Gold Taklon, fine details and shading.
Michael’s: 10pc “Artist’s Loft” white synthetic brushes.
Jerry’s Arterama: Pro Stroke-Power Creative, fine and medium brushes.
For Oil paintings, the best media is Refined Linseed Oil with Turpernoi. To clean the brushes Turpernoi. Glass container to mix media.
Ultra fine black Sharpie pen.
Easel (a simple table metal easel is fine).
Paper towel.
Paper/plastic plate and glass.

Painting Class acrylics oils-Tree in a Field of Lavender

Painting Class acrylics oils-Tree in a Field of Lavender

You can learn and enjoy to do this painting in the painting classes:
https://clinapolloni.com/painting-classes/

#paintingclasses #landscape #lavendersflowers #littleartgallerync #wakeforestnc #thecottonco #oilsclasses #acrylicsclasses #clinapolloniart #clinahpolloni #artistachilena #northcarolinaartist

Call Clina: 919-841-3132
Email: clinapolloni@gmail.com 

Visit Clina Polloni Art Studio and Gallery.
13 Garner Road, Franklinton NC 27525.
Take a drive to the beautiful country of North Carolina. Only half an hour from downtown Raleigh.

Serving Raleigh, Cary, Durham, Wake Forest, Franklinton and The Triangle Are of North Carolina.
Member of The Wake Forest Guild of Artists. Exhibiting at The Cotton Company and local business.

Contact Us
Tel: 919.841.3132
Email: clinapolloni@gmail.com

Serving Raleigh, Cary, Durham, Wake Forest, Louisburg, Franklinton and The Triangle Area of North Carolina.

WARNING, all paintings and photos are copyright © by Clina Polloni.

Visit Clina Polloni Art Studio Business website
Visit Portraits Paintings, Raleigh NC. Clina Polloni Portraits business site.

Member of the Franklin County Art Council and the Wake Forest Guild of Artists. North Carolina.

Clina Polloni received the 2017 Franklin County Art Council ARTIST AWARD.

New Paintings and Announcements